From Bulbapedia, the community-driven Pokémon encyclopedia.
The front cover of the Electric
The Pokémon Keychain Books are a series of four small books. Each book is focused on a specific type.
The series was published in Australia by Five Mile Press and in the United Kingdom by Reader's Digest Children's Publishing Ltd.
The four types featured are the Electric, Water, Normal, and Fire types. The books' covers show a holographic image of Pokémon evolution; the books themselves contain Pokédex information about the Generation I Pokémon of the specified type.
Each book has a keychain attached to the spine, hence the name of the series.
List of books