I was just starting out on outdoor climbing this year when I decided I had to get this book. 'Climbing Anchors' sounded to me at first like it dealt purely with setting up top-rope and belay anchors, but it has a wealth of information on placing trad gear as well.
The first half has detailed discussions on the different types of pro, ranging from natural pro to passive/active pieces and fixed gear. John Long talks about how (and how not to) use these protection systems. It's still pretty up-to-date circa 2008, with the only omission I can think of being the Omega Linkcams.
The latter part deals with falls forces and anchor-building, with a large portion devoted to equalizing anchors. Near the end Long introduces a new equalizing system called the equalette, which is both (somewhat) self-equalizing and resistant to shock loading if a component fails.
After reading this book, I gained enough confidence in gear placement that I was leading easy trad within my first season of outdoor climbing.
The book is well-illustrated throughout with both photographs and diagrams, and the author's assertions are backed with test data where available. It's also surprisingly readable, with the history of the various pieces of gear thrown in, as well as humorous anecdotes from his own climbing career.
Overall an important book for climbers and aspiring climbers to read.