The Color Harmony Manual is a color atlas based on the Ostwald color system and widely used for color selection and specification for several decades beginning in 1942. It has been out of print since 1972; however, many libraries have a copy of the third or fourth edition. This is a report on the history, the colorimetric basis and specification, and the use of the several editions of the Manual. Included are representative colorimetric data for the third edition. The Ostwald hue triangles and a color solid made with them portray and help explain the sensory world of color. Important sequences, the clears, lie on the outside surface of the solid. Color scales of equal blackness and whiteness are defined. Comparisons are made with the designs of the color charts in other atlases. An appendix concerning the third edition discusses a Descriptive Color Names Dictionary, availability of matching paints, a set of artists＇ colors, and production details of the colors.