Prima's Official Pokémon Strategy Guide
I have found this guide to be very informative, with sections such as: How I Became a Pokémaniac, How to Become a Master Pokémon Trainer, A Walk Through the World of Pokemon, The Complete Pokédex, All the Skills You Ever Need to Know, Items Galore!, and A Pokémon Check-List. In the Walk Through, it has detailed maps of every area, as well as what items are there and what Pokémon can be found there. In the Pokédex, it says each Pokémon's Evolution (what it evolves into, and how to evolve it), its Type, Height, Weight, Appearance (where you can find it), the description that appears in your Pokédex, any technical and hidden machines that it can learn, and any moves that it learns by itself and what level each is learned. I use this guide whenever I play Pokémon. It was well worth the small $15.00 I paid for it.