Nogizaka Haruka no Himitsu (乃木坂春香の秘密, Nogizaka Haruka no Himitsu? lit. Haruka Nogizaka's Secret) is a Japanese light novel series by Yūsaku Igarashi, with illustrations by Shaa. The series originally started serialization in volume thirty of MediaWorks' now-defunct light novel magazine Dengeki hp on June 18, 2002. One more chapter was published until the first bound novel of the series was released, though more chapters were later serialized in the magazine. The first novel was released on October 10, 2004, and as of December 10, 2007, seven volumes have been published by ASCII Media Works under their Dengeki Bunko label. A manga adaptation by Yasuhiro Miyama started serialization in the seinen manga magazine Dengeki Moeoh on August 26, 2006, also published by ASCII Media Works. An anime adaptation produced by Studio Barcelona aired between July and September 2008. A visual novel for the PlayStation 2 was released in Japan in September 2008.