Augustus James Pleasonton, often called A. J. Pleasonton (January 21, 1801 – July 26, 1894), was a militia general during the American Civil War. He wrote the pseudo-scientific book The Influence Of The Blue Ray Of The Sunlight And Of The Blue Colour Of The Sky, which was published in 1876. His book is often attributed to being the birth of contemporary chromotherapy. He was the son of Stephen Pleasonton and elder brother of Civil War-General Alfred Pleasonton.