Nogizaka Haruka no Himitsu (乃木坂春香の秘密 lit. Haruka Nogizaka's Secret) is a Japanese light novel series by Yūsaku Igarashi, with illustrations by Shaa. The series originally started serialization in MediaWorks' now-defunct light novel magazine Dengeki hp on June 18, 2004. The novelization ran from October 2004 to July 2012 by ASCII Media Works under their Dengeki Bunko imprint.
