There are 6 books in Kingdom Hearts Series.
A manga based on the Kingdom Hearts video game storyline has been released in Japan and the United States. It was divided into three manga series based on Kingdom Hearts, Kingdom Hearts: Chain of Memories, and Kingdom Hearts II. The first series, Kingdom Hearts, is listed below.
Other series related to Kingdom Hearts Series are Kingdom Hearts II , Kingdom Hearts II , Kingdom Hearts 358/2 Days and Kingdom Hearts: Chain of Memories .