Welcome to an adventure with one of the deep-sky's most marvelous and mysterious nebulae: an almost unimaginably gigantic cloud of dark interstellar matter that perplexed photographers and astronomers from the time of its discovery on an early glass negative: by a pioneering woman scientist!

     Read the untold saga, forgotten for more than a century and uncovered from historic documents published by Harvard but never again correctly quoted by all subsequent reference works. We present, with cooperation of the Curator of Historical Photographs of Harvard College Observatory, and the Mary Lea Shane Archives of Lick Observatory, the "History of the Horsehead Nebula", a year-long project undertaken in 1989-90 by amateur astronomer Stephen R. Waldee, assisted by many other individuals, both amateurs as well as celebrated professionals. Our story unfolds in three short articles originally written for ASTRONOMY Magazine, but never published; and then in a long, annotated scholarly paper -- believed lost for more than a decade but now at last recovered and reconstructed -- tracing the history of 19th century nebular studies related to dark matter and the Horsehead.

     Learn about famous astrophoto pioneers William H. Pickering, Edward Emerson Barnard, Max Wolf, Sir Isaac Roberts, Heber Curtis, and John C. Duncan and see their actual photos of the Horsehead. Explore the century of investigation made possible by the new development in science and technology that changed astronomy: photography. Read about the controversy swirling in 19th century professional circles about the possible existence of faint nebulae claimed to be seen only by William Herschel, and whether or not the sky's mysterious dark spots were "holes in the heavens". Find out how astronomers slowly came to understand that there were not only bright nebulae, but also dark ones. And enjoy stories of the personalities of the astronomers: their lives, loves, arguments, resentments, obsessions, and creative insights.