This chapter provides the reader with the basic notions for understanding color perception, which include the definition of terms like illuminance, luminance, and reflectance, as well as the description of the visible wavelength in the electromagnetic spectrum. After emphasizing the distinction between hue, brightness, and saturation, the crucial notions of primary colors and complementary colors are explained. Another fundamental distinction is then made between the additive color mixture, which might lead to the perception of white, and the subtractive color mixture, which might lead to black. Two classic theories of color perception are then described, the trichromatic theory of Young-Helmholtz and Hering’s opponent process theory, followed by the presentation of physiological evidence revealing that both theories contribute the overall process leading to color perception. Finally, several chromatic effects are reported, including simultaneous contrast and aftereffect, followed by the description of the main deficits of color perception.