I found the book very helpful regarding aspects that the the first part of the guide left out.
If you look in the previous guide for example, Mewtwo is mentioned that you
have to trade it over from another Pokemon game, however in this one, it
mentions that you can find it in Cerulean cave.
Another great feature with the book is the much expanded Pokedex, which tells you which TM's and HM's a pokemon can learn, which wasn't covered in the previous book. The book also includes the phone numbers of all the available trainers in the game and how to contact all 16 gymleaders for rematches. Having played Pokemon FireRed, I found the whole guide to the Kanto region interesting, even though I'd played through the region, in a different game, many times before.