We've already had a lengthy (and still active) thread attempting to address the question "What are the best textbooks, and why are they better than their rivals?". That's excellent, but no one is going to post there unless they're prepared to claim: Textbook X is the best on its subject. But surely many of us have read many texts for which we couldn't say that but could say "I've read X and Y, and here's how they differ". A good supply of such comparisons would be extremely useful.

I propose this thread for that purpose. Rules:

• Each top-level reply should concern two or more texts on a single subject, and provide enough information about how they compare to one another that an interested would-be reader should be able to tell which is likely to be better for his or her purposes.
• Replies to these offering or soliciting further comparisons in the same domain are encouraged.
• At least one book in each comparison should either
  • be a very good one, or at least
    
  • look like a very good one even though it isn't.

If this gets enough responses that simply looking through them becomes tiresome, I'll update the article with (something like) a list of textbooks, arranged by subject and then by author, with links for the comments in which they're compared to other books and a brief summary of what's said about them. (I might include links to comments in Luke's thread too, since anything that deserves its place there would also be acceptable here.)

See also: magfrump's request for recommendations of basic science books; "Recommended Rationalist Reading" (narrower subject focus, and without the element of comparison).