Sometimes scifi of this vintage can really suck, and I can't grok it at all. (See what I did there? Anyone? Okay, it's kind of lame.) Sometimes the upheavals of the late 60s in terms of race, gender and the like get glossed in scifi in lieu of a future dominated by Joe Blaster righting the imperial imperatives of whatever Federation, Empire, etc. One could even argue that gleaming beauty of the Federation on Star Trek acts as a foil for the redemption of the white male protagonist. See everyone, perfect is boring, and has the be counterbalanced with violence and sexual transgression. Not that I'm arguing that. One could. Please don't flame me. Anyway, this book rocks. The central exploration is of the power of language to shape perception, how some ideas are literally unthinkable because the structure of the language precludes the thought. The protagonist, a poet, is asked to look at a code for the military. She figures out that Babel 17 is a language, not a cypher. (Think using Navajo instead of Enigma during WWII.) From there it's off and running in a world that doesn't even pretend to be like our own.
Sometimes the ideas are more important in scifi than the execution. Characters aren't characters so much as philosophical place holders, descriptions turn into a sort of oral formulaic of white corridors and alien landscapes with two suns burning on the horizon. (Not that that doesn't rock too! Don't flame me!) In a book about language, you have to do better, and Delaney's prose has a poet's sensibility, compact and evocative.