From Bulbapedia, the community-driven Pokémon encyclopedia.
Pathways to Adventure is a series of books written by Jason R. Rich and published by Sybex Inc. The books in the Pathways to Adventure series are based on the plotlines of various video game series, including Pokémon. They are written from a third-person perspective and contain hints and screenshots of the games featured in the story.
There are four books about Pokémon games in the Pathways to Adventure series: Pokémon, which is based on the Generation I games, Pokémon Snap, which is based on the game of the same name, Pokémon Gold/Silver, and Pokémon Gold/Silver: The Adventure Continues!, which are based on the first and second halves of Pokémon Gold and Silver.
Aside from Pokémon, other books in the series include The Legend of Zelda: Ocarina of Time and Donkey Kong 64.