Managed Code Performance
Fresh from Dominic Cooney's great session at Code Camp Oz (on managed code performance), I finally got to finish a book from another friend Nick Wienholt. Maximizing .NET Performance (ISBN 1-59059-141-0) is a great read. I'm only sorry I ended up taking months to read it as it was the book I've been reading whenever I get spare time. I haven't had a lot of that lately.
Nick provides a great coverage of many aspects of the framework and I'd suggest this is a good book for all .NET developers to read, not just those wanting to tweak a bit more performance from their apps. I found the coverage of things like threading, app-domain loading, etc. to be really well-written. Recommended!