Miller announces from the beginning of the novel that he is not writing a book "in the ordinary sense of the word" (1.6), and we would advise you to take him seriously. He's definitely not about to present a clear, chronological novel. He calls it a "song," which it pretty much is—a song straight from his twisted psyche that hasn't quite been through the production phase.
The novel—or song—tells the story of roughly one year of Miller's life in Paris (and, briefly, Dijon) as he struggles to come to terms with himself as a writer. A plot summary of this novel is no simple task, but here's our stab at it:
Tropic of Cancer opens with Henry living at the Villa Borghese with Boris, his louse-ridden but generous friend. It's Miller's second Fall in Paris. Besides finding a roof to put over his head, he's basically just interested in writing and having sex with prostitutes, which is weird because he's broke. He has sex with all manner of women, most of whom remain nameless and pretty much faceless.
He recalls Mona, who sounds like she's the only woman he has ever loved, although he clearly has a thing for Tania as well. But because Mona was his wife, he saves a little place for her in his heart. We learn that Mona hasn't been around for a long time, but that it was love at first sight for those two. Aw. (We have to "aw" here because there aren't that many opportunities.)
Henry proceeds to recall a bounty of other prostitutes he's had sex with and provides the reader with some amusing anecdotes about his friends who are "cunt-struck" (1.14) and can't write to save their lives. But they loan him money, so yeah, it's all good.
Between anecdotes, there are long philosophical reflections about death, disease, the future, and what a capitalist pig-worshipping disaster America is. Germaine stands out as a fine example among prostitutes—a crowded playing field if there ever was one. She was worth spending the money Henry's wife had sent him. Lucky girl.
The good news is, now Henry has all sorts of material to write about. Everything would be beautiful and perfect if his buddy Carl would stop complaining about Paris and everything else under the sun. Henry also visits Tania, but she's with some crusty dramatist named Sylvester. You get to hear a lot about what an over-talker this guy is and how he has really bad dandruff. Ah, the details.
Things start looking sweet when our now-homeless narrator meets Serge, an enthusiastic Russian who puts Henry up in his bug-ridden apartment outside of Paris and provides him a few paltry crusts of bread in exchange for English lessons. The bed bugs and tapeworm soon become too much for even him, though, and he bails at the first chance he has.
Next up, Henry relates his high jinx with a man named Peckover, yet another sucker who loans him money. He also recalls some high adventure with a Hindu he had met back in his Brooklyn days. A rich pearl merchant, Nanantatee, had put him up in New York but got really bossy and manipulative. He basically turned Henry into his own personal houseboy.
Again, Miller can't stand the deal and leaves. His way out is Nanantatee's friend Kepi, whose sole mission is to set up clients with prostitutes. He enlists Henry to do some of that work, which turns into a comedy of manners involving one of Gandhi's men taking a dump in a bidet. None of these events presents any real obstacles to Henry's happiness, though, because he's a guy who decides to just live in the present.
Henry gets odd jobs along the way, like being a lowly proofreader for a newspaper, a job he enjoys for all of its tediousness—but then he gets fired, as he reports, for being smarter than his envious boss. As part of his constant quest to survive without doing anything too taxing, he takes a job in Dijon teaching kids at a shoddy school in the middle of nowhere. Surprisingly, these obligations become too much for him and he leaves without as much as an "up yours."
Back in the arms of Paris, Henry relaxes again, but he has to resume his search for someone to sponsor his wayward lifestyle. He indulges in food, women, and alcohol at every chance he gets. Oh, and he writes a little.
He consoles himself that Paris is far superior to America, which he sees as the land of lawn mowers and selfish rabbis and priests. Offering musings on the existential circumstances of his existence takes up a lot of the book—what with all of the homelessness, disease, and poverty all around him.
One of his final accomplishments is getting his pathetic friend Fillmore out of the clutches of his abusive and demanding pregnant girlfriend. When he packs Fillmore off to America, Henry gets a heap of cash and lives temporarily like a prince. Though he spends two seconds considering going back to America himself, he quickly turns to poetic reflections on the Seine River.
This guy's not going anywhere.