Color theory, in a very basic view, is the mixing of colors, typically in painting, to create new colors, or contrast others in such a way as to bring out the artists true vision in a given piece. Essentially, color theory is one element of art among many, such as line, form, space, value, and shape. Color theory, however, is much more than this, it is an actual science supported by the likes of Sir Isaac Newton and Goethe. Its history begins at the end of the 1800s with Munsells color cart. It became the Color Wheel which artists use today. The color wheel helps to define the reaction between colors for use primarily in art and painting. An understanding of color theory allows the artist to create works that have a directed emotional and psychological impact. Color, then, has the ability to cause reactions of a controllable sort within the viewer. An understanding of those reactions through the use of Color Theory allows the artist to further manipulate the viewer as well as the consumer. It is the purpose of this paper to examine the history of color theory, how it is applied now, and why it is so effective.