The original manga series began its serialization in 2005 as a prologue one-shot and ended last November. Shueisha published the manga in 30 compiled volumes. The manga won the 32nd Annual Kodansha Manga Award for Best Shoujo Manga, and was nominated for the 1st Manga Taisho Award in 2008. Two anime adaptations by Production I.G aired in Fall 2009 and Winter 2011, running for 25 and 12 episodes, respectively. A live-action movie premiered in Japan in September 2010.
Viz Media has licensed the manga for North American release, and published the 28th compiled volume on January 2. NIS America licensed both anime seasons for North American distribution and released them in three Blu-ray and DVD volume between January and July in 2012.
Source: Comic Natalie