Kingdom Hearts (novels)

The Kingdom Hearts novels are a series of books that are based on the games of the Kingdom Hearts series. They have only been released in Japan and have not been confirmed to receive publication anywhere else. They are all written by Tomoco Kanemaki and the covers are illustrated by Shiro Amano who also did the manga of the Kingdom Hearts series. They are all published by Square Enix.

Kingdom Hearts (novels)
This part of the series covers the first Kingdom Hearts game and was released in two volumes. This series was also co-published by Disney Press.

Kingdom Hearts: Chain of Memories (novels)
This part of the series is about the game Kingdom Hearts: Chain of Memories and was released in three volumes. The first two volumes of this series is Sora's story while the third and last volume is Riku's story.

Kingdom Hearts II (novels)
This part of the series is about Kingdom Hearts II and was released in four volumes with first one being about Roxas's story.

Kingdom Hearts 358/2 Days (novels)
Recently announced is a new series of Kingdom Hearts novels is based on the game Kingdom Hearts 358/2 Days. So far, only the first and second chapters have been translated. The third novel is set to release on May 28th in Japan.

Short Stories
These are short stories from the main novel series that did not get put in. The original plan or concept for them is done by Tetsuya Nomura and Kazushige Nojima.
 * Vol. 1 - Other Diamonds
 * Vol. 2 - Axel-Seven Days

Other
Roxas-Somewhere in Time

Released along with Kingdom Hearts II Final Mix as a bonus to those who pre-ordered the game.