Garrett Putnam Serviss (March 24, 1851 – May 25, 1929) was an American astronomer, popularizer of astronomy, and early science fiction writer.

Serviss showed a talent for explaining scientific details in a way that made them clear to the ordinary reader, leading Andrew Carnegie to invite him to deliver The Urania Lectures in 1894 on astronomy, cosmology, geology, and related matters.

With Carnegie's financial backing, these lectures were illustrated with magic lantern slides and other effects to show eclipses, presumed lunar landscapes, and much else.

Serviss toured the United States for over two years delivering these lectures[citation needed], then settled down to become a popular speaker in the New York area.

[citation needed] He worked with Max and Dave Fleischer on The Einstein Theory of Relativity (1923), a short silent film released in connection with one of Serviss' books.