This might just be the best single-author SF collection I've ever read. Chiang isn't a typical SF author in at least two ways - he won the Nebula award for his first published story, and in over twenty years he's published fewer than twenty stories, in marked contrast to the genre's usual manic overproduction - but what a shame there aren't more like him. There are eight stories in this collection, namely:
Tower of Babylon
Understand
Division by Zero
Story of Your Life
Seventy-Two Letters
The Evolution of Human Science
Hell is the Absence of God
Liking What You See: A Documentary
They're all completely different from each other, seven of them are masterpieces by any reasonable standard and the other ("The Evolution of Human Science"), a short-short, is damned good as short-shorts go. Despite their difference from each other, Chiang's stories are all characterised by lucid prose, deep humanity and amazing inventiveness. Way back in the seventies, Ed Ferman and Barry Malzberg produced an anthology, "Final Stage", which attempted to be the "ultimate" SF anthology, by asking authors associated with particular SF themes to produce the definitive story in that category. The results then were patchy at best, but damned if Chiang hasn't pretty much done the job single-handedly.
In other words:
"Tower of Babylon", though you may not spot it at first, is an absolutely classic space exploration narrative, albeit one where the cosmology is utterly different from our own universe. "Understand" is a gripping riff on superhuman powers, so smartly done it takes a while to notice it's kinda Prof X versus Magneto writ large. "Division by Zero" is a New Wave story, in which scientific theory is a metaphor for a very human problem (a distant relative of Pamela Zoline's "The Heat Death of the Universe", for those with long memories). "Story of Your Life" combines the first contact, alien language and conceptual breakthrough motifs to shattering, somewhwat Tiptree-esque, effect. "Seventy-Two Letters" mashes up Steampunk with the "what if magic was a logical, rigorous science" idea. "Liking What You See: A Documentary" is clever social satire notable for its compassion to people on both sides of the argument. As for "Hell is the Absence of God", it's absolutely sui generis - is it SF, slipstream, fantasy, fabulation, magical realism, New Weird or what? It doesn't matter. It's a brilliant, totally original idea and a profoundly moving story.
But then they're all moving. What differentiates Chiang from almost all the other SF writers out there is not just how wild yet well-worked his ideas are (which is plenty), but also how well he integrates them into human dilemmas involving characters you genuinely feel for. There's no-one like him, and he's displaced Howard Waldrop - who's been in place for over twenty years - as my choice for a Desert Island single-author collection.
PS Please note there's a very minor, slightly annoying formatting issue with the Kindle edition (it randomly prompts you to click to footnotes).