For serious developers only -- but perfect for the right audience

This is exactly what I want from a technical book on a tricky, subtle topic: it is *serious* and does not kid around. If you're new to programming, XML, declarative languages, or regular expressions: this is not the book for you. If you're familar with all those things and want to put a new tool in your toolbelt, this is the book. It explains the semantics and the processing model thoroughly, instead of just describing the syntax. It also serves as a reference for XSLT 1.0, because the author carefully indicates what features are available in which version.
I recommend getting the companion XPath book XPath 2.0 Programmer's Reference (Programmer to Programmer) at the same time; the XSLT book doesn't cover XPath, but you really need solid XPath skills to accomplish anything with XSLT.
Just one problem: the diagrams are really ugly. They weren't designed for print; they're jaggy and blurry. I've seen the same diagrams in other materials though; I think it's part of the XSLT spec.

Other Reviews

• Lousy design/layout impairs usability
• For serious developers only -- but perfect for the right audience
• Not a stand-alone book, terrible format for reference