"Inherent Vice" has a number of meanings. See Inherent Vice Title. The phrase appears on pg. 351.
The cover illustration is by Maui artist Darshan Zenith (see his Official site). The piece is called "Eternal Summer," and subtitled, "A 'Retired' Caddy Hearse Greets Daybreak at a Beach Surf Shop." Prints of the painting can be purchased here. The 1959 Cadillac Hearse is parked in front of the "Endless Summer Surf Shop" (namechecking the Beach Boys Greatest Hits collection and Bruce Brown's 1966 surfing documentary!).
More info at Inherent Vice cover analysis
Book jacket description
Pynchon himself wrote the copy to the book jacket description of Against the Day (text here). It is possible that Pynchon did the same for Inherent Vice.
Under the paving-stones, the beach!
"Sous les pavés, la plage" - slogan dating from the 1968 Paris student riots. Wikipedia Literally, it refers to the paving stones thrown at the police and to the discovery made by the rioting students, after prying up the stones, that there was sand underneath. Figuratively, it uses the metaphor of a beach to allude to the ideal life to be found beneath the confines of society.
For those interested in such things, here is an odd and fairly lengthy online discussion about the phrase and its translation which, if nothing else, gives a flavor for how translations can go awry when people start trying to translate metaphors instead of words.
Like Against the Day, Inherent Vice has no dedication. Pynchon dedicated three of his previous novels to friends and family: Mason & Dixon ("For Melanie, and for Jackson"), Vineland ("For my mother and father"), and Gravity's Rainbow ("For Richard Fariña").
Country Joe & the Fish T-shirt
A Berkeley-based rock band most widely known for musical protests against the Vietnam War, from 1966 to 1971
Tonight she was all in flatland gear,
Night, Tuesday, March 24, 1970, first day of the narrative. It's a lot harder to assign real-world dates to the first half of the narrative than to the second half. It could be some kind of "parallel time" (see page 128). Many events in the first half of the book do seem to echo events in the second half.
Shasta is a soft drink brand that reached the peak of its popularity in the 1980s. Wikipedia. Note that Pynchon has named characters after soda before, e.g. Wicks Cherrycoke in Mason & Dixon.
However, more to the point, "Shasta" is name-connected to Mt. Shasta, long believed by some to be where the Lemurians came after Lemuria sunk into the sea. They also believe in the presence of Bigfoot here, as well as wolfmen. See Mt. Shasta and the Lemurian Connection. Pynchon is likely familiar with this mythology. Vineland, set in pot country of Northern California, alludes to Yurok myth, and his other works draw on mythology from many traditions.
"Shasta McNasty" was also the name of a fictional band, the subject of a short-lived UPN sitcom. The members of the band were three slackers who lived in Venice Beach.
They stood in the street light through the kitchen window  there'd never been much point in putting curtains over and listened to the thumping of the surf from down the hill. Some nights, when the wind was right, you could hear the surf all over town.
Like Vineland, and Gravity's Rainbow, here a Pynchon book begins with light coming through a window. Also like Vineland, the sentence structure and rhythm is just slightly jarring - that '...in the street light through the kitchen window...' seeming to echo Vineland: "Later than usual one summer morning in 1984, Zoyd Wheeler drifted awake in sunlight through a creeping fig that hung in the window, with a squadron of blue jays stomping around on the roof." In both cases, it's just a little odd that Pynchon doesn't refer to the light 'that shone' through the window. And that creeping fig makes an appearance on page 36 of Inherent Vice.
makeup supposed to look like no makeup or whatever,...
The "natural look" was popular during the 1970s. Ads told woman that makeup was invisible, "the makeup that is and isn't." Another ad sez "It looks so convincing you'd swear it isn't makeup." (See: Disco divas: women and popular culture in the 1970s By Sherrie A. Inness, page 21)
Advice column started in 1956 by Pauline Phillips and written under the pen name of Abigail Van Buren. Her daughter, Jeanne Phillips, writes the column today. Oddly, Pauline's twin sister, Eppie Lederer, also wrote an advice column, 'Ask Ann Landers'.
Just south of Hollywood, and one of the most desirable locations in Los Angeles. Hancock Park was developed by the Hancock family and is named after developer-philanthropist G. Allan Hancock, with profits earned from oil drilling in the former Rancho La Brea, home of the famous tar pits. Wikipedia
"Can't Buy Me Love"
This well-known Beatles hit has a curious connection with two other Beatles tunes touched on in The Crying of Lot 49. "She Loves You" is cited outright and there is the parody title "I Want to Kiss Your Feet" in reference to "I Want to Hold Your Hand" by Sick Dick and the Volkswagens (Volkswagens are commonly referred to as Beetles). The German language versions of "She Loves You" and "I Want To Hold Your Hand" were recorded at the same session as "Can't Buy Me Love." Wikipedia entry for "Can't Buy Me Love"
An "Afro" pick, aka a comb for the Afro hairstyle; this doesn't necessarily mean Doc has an Afro, only that he borrowed one "for protection" because they generally had fairly sharp metal tines. [But Tariq Khalil on p. 14 stares at Doc's "Afro." TRP notes that his stare, "under different circumstances," would be "offensive"--whatever that may mean.]
Evelle Jansen Younger, District Attorney of Los Angeles County 1964-1971, Attorney General of California from 1971-1979. Wikipedia
Wilton Norman "Wilt" Chamberlain (August 21, 1936 – October 12, 1999), stood 7'1" tall and was one of the greatest centers ever to play basketball in the NBA. Throughout his storied career he played for several teams, including the Los Angeles Lakers from 1968-1973. He later played in and was president of the International Volleyball Association. He once claimed to have had sex with 20,000 women over the years. Wikipedia
DayGlo is a tradename, and a common name for blacklight ink or blacklight-reactive ink that glows under a black light, a source of light whose wavelengths are primarily in the ultraviolet. The paint may or may not be colorful under ordinary light. It is also known as fluorescent paint. Very popular in the 1960s and 1970s.
Night, Tuesday, March 24, 1970, first day of the narrative.
1959 Cadillac Biarritz
a luxury version of the Eldorado. Wikipedia.
This fictional Los Angeles beach town where Doc lives and works is, according to the article "Thomas Pynchon and the South Bay" Pynchon's fictionalized Manhattan Beach where he lived in 1967-1971—/CW/ at 217 33rd Street—while working on Gravity's Rainbow And in Vineland, Gordita Beach is where Zoyd Wheeler lived "shortly after Reagan was elected governor of California" (on Jan 3, 1967):
- Zoyd was living down south then, sharing a house in Gordita Beach with elements of a surf band he’d been playing keyboard in since junior high, the Corvairs, along with friends more and less transient. The house was so old that all of its termite clauses and code violations had been waived, on the theory that the next moderate act of nature would finish it off. But having been put up back during an era of overdesign, it proved to be sturdier than it looked, with its old stucco eaten at to reveal generations of paint jobs in different beach town pastels, corroded by salt and petrochemical fogs that flowed in the summers onshore up the sand slopes, on up past Sepulveda, often across the then undeveloped fields, to wrap the San Diego Freeway too. (p. 22)
- Pynchon owned a '65 Corvair. the car was so light that one he did a wheelie on the freeway for which the cure was putting a 50 pound bag of cement in the truck which was in the front of this rear wheel drive car-CW?
The Corvairs surf band figures in Inherent Vice, as well.
- MAD Magazine-style substitution pun in the name, Gordita Beach: from the Manhattan, an open-faced hot sandwich made with meat and gravy (although there are several different "Manhattan" sandwiches ), to the Gordita, a thick tortilla stuffed with meat stew.
The Watusi is a solo dance that enjoyed brief popularity during the early 1960s. Its name came from the Batutsi tribe of Rwanda.
Reet (short for Rita?) is a slang term meaning "right" or "proper". Although it originated in the north of England, the term was also frequently used in LA at the time of this novel.
Reet’s a real estate maven, and her name puns on REIT, or real estate investment trust, a company that buys up malls, office buildings, shopping centers, apartments and master planned communities like Channel View Estates.
Section of Manhattan Beach west of Sepulveda Blvd, filled with family homes. Generally more upscale than Doc's neighborhood. The moniker comes from the streets all being named for trees.
2001: A Space Odyssey
This 1968 film by Stanley Kubrick is also mentioned in chapter 14 of Vineland. It includes a computer named HAL that gains consciousness and kills the ship's crew members. Talking computers also show up on pg. 115 of Vineland.
Pynchon apparently wrote a letter to his editor, Cork Smith, in the 1960s saying that he was working on two books: one on Mason & Dixon, and one loosely inspired by Godzilla. See Crying of Lot 49 Chapter 3 & Vineland, page 142. It was recounted by Pynchon to his friends that to continue to collect royalties he had to come up with the sentence from his next book. The sentence was something like "Hiro stood in the wreckage of what was once downtown Tokyo and as he looked down at the giant footprint he explained to the insurance adjusters in his Japanese accent 'clearly reptilian.'" [This anecdote is spurious at best. Is there a source for this? Any evidence?]
White prison gang, also known as The Brand, the AB, or the One-Two, formed by a group of bikers in 1964 at San Quentin State Prison. Wikipedia
Channel View Estates
The Channel Islands are a chain of islands off the coast of southern California.
The name is perhaps intended as a telling contrast with "River View" (or "Riverview"), a common name for neighborhoods, real-estate developments and towns. Wolfmann's development is a "chipboard horror" - basic tract housing for the newly middle-class - and it has no river to view, only a drainage channel. "Ditch View Estates" might have been more pointed, if less believable.
Possibly a reference to "channels" on a television set with countless "viewers" looking at the tube in the Los Angeles city sprawl of future single-family homes.
Bjornsen="son of the bear" in Swedish and Norwegian. The Old English equivalent of Bjorn is "Beorn", the name of the shapeshifter in The Hobbit who assumes the form of a bear. 
Flying Nun, The
The Flying Nun (ABC sitcom '67-'70) starred Sally Field (who also played surf bunny Gidget in an earlier sitcom) as a young nun with a talent for catching the wind like a wave. Despite the reference to Bigfoot playing "comical Mexicans," the series actually took place in Puerto Rico. Wikipedia
Voyage to the Bottom of the Sea
TV show running on ABC from 1964-68 based on a 1961 movie by the same name. It featured the adventures of the world's first privately owned nuclear submarine, the SSRN Seaview. Many of plots were based on contemporary political issues, though some 'monster' episodes appeared as well--think Star Trek in the ocean. Wikipedia
An anagram for Zoyd, one of the main characters in Vineland. Also Zody's, a chain of discount stores Wikipedia.
If Used-Car dealer Cal Worthington didn't exist, someone would have to invent him. Famous for his TV ads throughout California and his dog "Spot" [usually an exotic animal] the many parodies of Cal never exceed his own bizarre ads. YouTube Worthington's ads were parodies themselves of an escalating competition between auto dealers to try to get viewer attention. The "dog" Spot was a riff on the German Shepherd (actual) dog featured in the commercials of the biggest multi-lot dealer, Ralph Williams. While Worthington looked and dressed like a typical East L.A. Okie and played country & western music on his own show, "Cal's Corral", he was actually cognitively aligned more with Doc's scene, among other things, sponsoring the left-wing television show of Mort Sahl.
Hunter S. Thompson ran unsuccessfully for mayor and sheriff of Aspen, Colorado in 1969 and 1970. Wikipedia Unsure if "freak power" was a term Thompson coined?
W. C. Fields
American comedian, actor and juggler (1880-1946). Fields created one of the great American comic personas of the first half of the 20th century: a misanthropic and hard-drinking egotist who remained a sympathetic character despite his snarling contempt for dogs, children, and women.
“... oh, here, finish this up if you want.”
Denis is offering Doc a roach (the remainder of a marijuna cigarette) that is still burning.
“Thanks, all’s ‘at’ll do’s just burn my lip.”
Apparently, Doc is declining the offer because the roach is so small it can barely be held with fingertips and, even if held by a roach clip, would become a tiny hot coal at the instant of inhalation as air was sucked through it. Whether held by fingers, touched to lips, or inhaled into the mouth, such a roach was only fit for someone desperate for a buzz. Thus we learn Doc is not desperate and suppose Denis would have reserved more to offer if he were more of a friend. N’ertheless, the herb begs to be shared with kindred spirits so Denis made the offer pro forma.
“...like Godzilla always sez to Mothra--why don't we go eat some place?”
A joke based on the fact that entire cities are often destroyed in these monster movies.
Real song released in 1969 by the fictional band The Archies which was 'composed' of the main characters in the Archie comic book series. The song was recorded by session musicians and released in the context of the Tube series The Archie Show. It remains a paragon of the Bubblegum Pop genre.
Gottlieb is a corporation that makes pinball machines and arcade games. Pynchon has a history with pinball tables going back at least as far as Gravity's Rainbow. Sidney Gottlieb headed the CIA's MK-Ultra project, way back in 1953. Wikipedia
A store specializing in recreational drug paraphernalia. When Doc indulges Denis, who craves munchies of which Doc's fridge is lacking, Doc meets up with Enseneda Slim who is the owner of the head shop Screaming Ultraviolet Brain.
Sad but true, as Dion always sez.
"Runaround Sue" ("Here's my story, it's sad but true...") was a 1961 hit for Dion DiMucci (b. 1939). Dion only sez it once, but then again he "said" it everytime the song was played. Have a listen on YouTube...
Playa Vista High
Mira Costa High is the high school in Manhattan Beach ("Gordita Beach" in Inherent Vice).
Denis came back with his Pizza.
Pynchon had a passion for pizza and had proposed making a film with the FPS group of San Francisco entitled "Mondo Pizza".
This happened at the Pipeline every Tuesday
Night, Tuesday, March 24, 1970, first day of the narrative. This establishes this day as Tuesday.
Someone who "traces" the location of people who have "skipped" town. Wikipedia entry...
The act of divining the future by casting lots, also Sorcery; witchcraft. Middle English, derived from old French via Medieval Latin sortilegium, from sortilegus, diviner : Latin sors, sort-, lot + Latin legere, to read. see Answers.com.
wasn't that they were fucking, exactly, but it was something like that.
This sentence structure is a Pynchon trademark found throughout his works: "not X, exactly, but Y..." For instance, Gravity's Rainbow, pg 137: "...you begin to wait for something terrible not exactly an air raid but something close to that."; Gravity's Rainbow, pg 580: "Not as an enterprise, exactly, but at least in the dance of things."
though, when Doc finally woke up
Morning, Wednesday, March 25, 1970, second day of the narrative.
He stumbled up the hill to Wavos and had breakfast with the hard-core surfers who were always there.
Huevos [pronounced, in Southern Californian American English, Wave-ohs] Rancheros: fried eggs served on corn tortillas with salsa, a popular dish with surfers, dopers, and other beach people in the sixties and seventies. A pretty good joke from Pynchon: huevos-wavos-surfer restaurant.
dinged-up El Camino, the one with the 396
A 396 is an engine with a displacement of 396 cubic inches (6.49 liters). This is a large V8 engine in a lightweight coupé utility vehicle.
Tomorrow is another day
For those who don't mind spoilers, see later annotation. Bigfoot's clichéd quotation is also the slogan of one of the most famous characters in U.S. literature, Scarlett O'Hara, the heroine of Margaret Mitchell's Gone With the Wind (1936). Needless to say, in the universe of pop culture allusions in Inherent Vice, this one is definitely an outlier, one of the weirdest, though Mitchell's novel (and the even more popular movie based on it ) were still popular in the '50s and '60s, especially among older generations. The quotation definitely establishes Bigfoot's cultural taste as being anomalous to the world of Doc and Gordita Beach.
If the Italianesque "stewardi" is being suggested by TRP as the plural of stewardess, what is "stewardii"--the plural of a plural? Definitely some comic linguistic play going on here, working out an alternative to to the clunky "stewardesses." Or could this refer to male airline attendants, "stewards" in the plural in non-Pynchonian parlance? Probably not, given that it's 1970 and airline attendants then were all female. Just a few fun things to think about while you're parsing the long list of all those waiting in line.... This is really just a pseudo-Latin joke, playing on the fact that "stewardess" phonetically sounds like a Latin noun ending in "-us." Such nouns (which, ironically, are masculine) become plural by changing the "-us" to "-i."
What's that? Pregnant women who are vegetarians and believe they need special "vitamin" supplements?
Frederick's of Hollywood
Famous retailer of lingerie, started by Frederick Mellinger (inventor of the push-up bra) in 1946. The original flagship store was a landmark on Hollywood Boulevard in Hollywood, California. Wikipedia
a rendering of a giant bloodshot eyeball
The logo for LSD Investigations might be a parody of the logo for the Pinkerton National Detective Agency, a famous and long-running agency started in the nineteenth century. Their logo is an eyeball with the phrase "We Never Sleep." See it here. This agency's activities play an important role in Pynchon's previous novel, Against the Day.
Famed Poster artist and surfer dude Rick Griffin also made a finely detailed rendering of a bloodshot, flying eyeball in this famous poster for a Jimi Hendrix concert at the Fillmore in 1968.
There also may be an allusion here to the most famous "giant eyeball" in 20th-century American literature, in F. Scott Fitzgerald's The Great Gatsby. The eye-doctor Dr. T. J. Eckleburg's giant billboard ad for his practice features a pair of eyes and glasses looking over a wasteland near a highway on the way to New York City. In FSF's words, "his eyes, dimmed a little by many paintless days under sun and rain, brood on over the solemn dumping ground."
psychedelic favorites green & magenta
A Pynchon leitmotif, the color combo of the faux-neon font of Inherent Vice's cover, also cited in Gravity's Rainbow & Vineland.
Karmic imbalance is an important theme in Vineland. See pg. 173, for example.
Sledge Poteet was a member of the film collective 24fps from Vineland. He shared, along with ninjette DL Chastain, "a fondness for enlightenment through asskicking."
Olivetti Lettera 22
A portable typewriter. See it here. Various sources, including Jules Siegel, note that Pynchon used an Olivetti Portable Typewriter.
(So did Cormac McCarthy, who used a slightly different model, a light blue Olivetti Lettera 32, to type all of his novels from The Orchard Keeper to The Road! McCarthy bought his Olivetti for $50 at a Knoxville Tennessee pawnshop in 1963. It was sold for over $250,000 at auction in 2009, with proceeds going to the Santa Fe Institute, a nonprofit scientific research organization. Wonder what the future of TRP's Olivetti will be.)
Black Guerrilla Family . . . George Jackson's outfit
The Black Guerrilla Family was a prison gang founded in the mid-1960's by George Jackson in San Quentin prison.
This is a potential anachronism. The novel ostensibly takes place in 1970, since it is after Charles Manson's arrest in December 1969 but before the trial began in mid-1970. However, many reports indicate the L.A. street gang that would eventually be called the Crips was not founded by Raymond Washington and Tookie Williams until 1971, and it was originally called the Baby Avenues, then the Cribs, and finally Crips.
Watts . . . the riots
In 1965, there was a widespread and brutal riot in the streets of Watts, CA. It lasted almost a week and resulted in several deaths and hundreds of injuries. Read more here. Pynchon wrote on the subject in his 1966 essay for the New York Times A Journey Into The Mind of Watts
"As Sledge said, you are a crazy white motherfucker."How can you tell? "I counted."