This is a new novel in the works, by Orson Scott Card. It's the sequal to Ender's Shadow, making it the 6th book in the Ender saga. This one tells the tale of the friends and comrades of Enders who were left on Earth, while he traveled the the space colonies. It also, of course, tells of his brother, Peter,'s rise to power. The first 5 chapters are on Orson Scott Card's web page: www.hatrack.com .
Other books in the Ender's Game Series