The fourth and best film by second-generation Brooklyn boho Noah Baumbach, The Squid and the Whale is partially autobiographical, and it seems as uncensored and intimate as entries from someone’s diary. Indeed, this squirmily hilarious study of a dual-Ph.D. family feels so anecdotal that its careful structure is not immediately obvious. Yet the writer-director, whose previous efforts include Kicking and Screaming and Mr. Jealousy, knows exactly what he’s doing. The action begins on an interior tennis court, in or near Park Slope, where 16-year-old protagonist Walt Berkman (Jesse Eisenberg) is about to begin a doubles match with younger brother Frank (Owen Kline) and their parents, Bernard (Jeff Daniels) and Joan (Laura Linney). “Mom and me versus you and Dad,” announces Frank, and that’s exactly how the story proceeds.

An author and literature professor, Bernard has lost none of his presumption as the acclaim for his novels has waned. He knows which books, films, and tennis players are genuine and which are not, and his highest compliments are such words as “dense” and “risky.” Walt follows this example, often recycling or mangling his dad’s judgments, as when he proclaims A Tale of Two Cities “minor Dickens” or The Metamorphosis “very Kafkaesque.” Taking the quick path to authorship, he decides that he wrote Pink Floyd’s “Hey You” and plays it for his impressed family. Then his parents announce what is supposed to be a dignified, amiable divorce, with an every-other-night commitment to joint custody, and the boys choose sides just as Frank said. Before long, Walt is calling his mother “whore.”

This is a withering self-portrait, as well as a forthright account of some minor New York celebs. (Baumbach’s father is a novelist, his mother a former Village Voice film critic.) While the details are reportedly not drawn from life, the emotions seem entirely true. The easygoing but self-centered Joan proves remarkably capable of simply continuing her life, beginning a successful journalism career and an affair with an unintellectual tennis pro (Billy Baldwin). Across Prospect Park in an “elegant” new home that’s actually a wreck, Bernard seethes, bitches, and counts every penny. His life becomes even more complicated when he unwisely allows the sexiest of his students, Lili (Anna Paquin), to move into a spare room. A more capricious cutie than the similar Katie Holmes character in Wonder Boys, Lili flirts with both Bernard and Walt, leading the latter to downgrade his provisional same-age girlfriend (Halley Feiffer). Meanwhile, the largely unsupervised Frank discovers alcohol and masturbation—and can’t keep these breakthroughs to himself.

Named for a diorama at Manhattan’s American Museum of Natural History, The Squid and the Whale is not a great-looking movie. But it does boast Baumbach’s best script to date, which offers a suitably jaundiced insider’s view of ’80s New York highbrows. (After the divorce, the only household valuables the grown-ups attempt to hide from each other are their books.) That the director is well-connected is revealed by the cast, which includes the son of Kevin Kline and Phoebe Cates and the daughter of cartoonist and writer Jules Feiffer, as well an impeccable selection of “downtown” rock and minimalism, including the Feelies, Lou Reed, Dean Wareham and Britta Phillips, and Reich’s Music for 18 Musicians. Baumbach’s not showing off, though. This is just his world.

He understands that world well enough to recognize its absurdity, in a realization that presents the key to appreciating the movie: It’s OK to laugh. With all the anguish, humiliation, and seeming revelations on the screen, some viewers watch in stunned silence. But the events that inspired the screenplay transpired 20 years ago, and Baumbach has had time to fathom their silliness. Aided by Eisenberg’s earnestness, Linney’s distance, and Daniels’ vanity-free embodiment of an educated buffoon, the director locates an equal measure of humor and horror in such everyday remarks as “I’m taking the cat.” As droll as it is pitiless, The Squid and the Whale can be paid the ultimate compliments: It’s dense, risky, and very Baumbachesque.