"First published in 1821, it paved the way for later generations of literary drug users, from Baudelaire to Burroughs." Whee!
While this is maybe not indispensable, it's also not more than 100 pages, so it gets five stars based on its ratio of awesomeness vs. time commitment. And it is
pretty awesome. De Quincey is funny and weird and literate, and the roots of all kinds of drug stories - from those quoted above to Trainspotting and, oh, A Million Little Pieces - are clearly visible.
In one of those proud yet crushing moments where you realize that thought you were so psyched about of has, as Public Enemy said, been thought before: I've always thought that people get more honest when they drink, so if that nice new friend of yours gets weirdly mean and creepy when he's drunk, you might want to think twice about inviting him to your wedding. And here's de Quincey: "Most men are disguised by sobriety; and it is when they are drinking that men display themselves in their true complexion of character."
That's from page 46, in the middle of an absolutely glorious comparison of the effects of wine and opium. One of my favorite passages because, unlike opium, I'm quite familiar with the effects of wine. "The pleasure of wine is always mounting, and tending to a crisis, after which it declines." Really, there's no sense quoting more of it; the whole two pages is great.
If you're interested in drugs, or wine, or the idea of a counter culture, or pretty writing, or the history of opium and its significant effect on the world, this is worth an afternoon.