John H. Chalmers is a retired astrobiologist and prebiotic chemist from the University of California, San Diego. In addition to working in the fields of genetics, industrial microbiology, biochemistry and chemistry, he has had a long-term interest in microtonality and is the author of “Divisions of the Tetrachord,” a book inspired in part by Ervin Wilson’s work. Chalmers is also an actor with the Village Church Community Theater in Rancho Santa, California, where he resides, and has recently become a computer artist, having exhibited his music-theory generated polychrome plots in a number of venues in San Diego and one in San Francisco.