@odd My advice: Start small. He’s got several books that are true doorstops, which can be intimidating. The Crying of Lot 49 is his shortest, and Inherent Vice has been made into a movie, so you could watch the movie, then try out the novel. If you dig these two, then you can try to tackle his longer books.
His two masterworks are Mason & Dixon and Gravity’s Rainbow. They are both long, gorgeous, trippy, and absolutely ruthless in their indictment of colonialism and capitalism. And also, fucking hilarious even while they are occasionally horrifying.
I fell into his books as a teenager, which permanently warped me, so I have Very Strong Opinions about what to read first, second, etc — and also about what not to expect. For one thing, he’s actually not a “post-modernist” like, say, David Foster Wallace or William H Gass. He’s got much more in common with true Modernists like Virginia Woolf, Gertrude Stein, Robert Musil, Djuna Barnes, Zora Neale Hurston, William Gaddis, and Ulysses-era Joyce.
He is a post-modernist in the sense that he reads like someone put Wittgenstein’s Philosophical Investigations and Piers Plowman in a blender with the Encyclopedia Britannica, every Coen Brothers movie, every Marx Brothers movie, the first season of True Detective, all the early seasons of The Simpsons, and a boxful of MAD Magazines, Krazy Kat, and silver age DC and Marvel comics. He’s like Don DeLillo but zany, Cormac McCarthy but funny (though to be fair, Suttree is actually hilarious).
Pynchon is a true outlier in English-language fiction, and (like other outliers such as Ishmael Reed, Lucy Ellmann, or Rudolph Wurlitzer) he has much more in common with Latin American writers like Borges, Cortázar, García Marquez, and Bolaño — or other European authors like Krasznahorkai, Umberto Eco, Ingeborg Bachmann, Georges Perec, Robert Walser, Kafka, even Rilke…
But he also has a lot in common with science-fiction writers like John Brunner, Anna Kavan, Philip K Dick, Arkady and Boris Strugatsky, or Gene Wolfe.
And honestly, he’s not actually hard — or rather he’s not nearly as hard as the snobs would have you believe. He’s just very, very weird.
But then, we live in a golden age of weird: Lost, Black Mirror, the Watchmen series, and Lovecraft Country are all very Pynchonesque, and so is Community and BoJack Horseman. And, further back in time, the original Batman from the 60s (with Adam West), as well as Mary Hartman Mary Hartman, It’s Garry Shandling’s Show, Better Off Ted, and The Prisoner.