Luna Mendax is the eleventh short story published in the Horus Heresy that was not originally part of an anthology novel. It was originally included in The Black Library Anthology 2013/14 which was released exclusively at the Black Library Weekender Event in November 2013. Luna Mendax was later released as an individual e-book on January 25, 2016 as part of the "Tales of the Knights Errant" week on the Black Library's website. It is also now included in The Silent War anthology novel. Covers for both the original and updated artwork is shown.