Good intro book. Provides references for further reading. Provides specific training plans--but we'll see if they work!
You're lying there on the couch, watching the Ironman in Hawaii. Wow, those people look fit! You could never do that, could you? Absolutely! This is an in-depth guide to everything you need to do to get yourself out on that beach -- from what gear you need, to nutrition, to training programs, to skill development. If you get one book on triathalons, this is the one.