The Unicorn: A Mythological Investigation was first published in 1881. It covers some of the same ground as the more popularly oriented Lore of the Unicorn, by Odell Shepard, before it ventures into comparative mythology. The present volume was written in the late 19th century at a time when all mythological and folklore narratives were believed to be astronomical metaphors. Brown sees the Unicorn as a lunar symbol, and draws on mythology from a wide range of sources to make his case, from Northern European to Vedic and Zoroastrian.