What is color and how it is perceived?

The physical nature of color is well known and is based on its wavelength; however, the color perception in humans and animals is much less understood and is based mostly only on some assumptions and theories. We present the current knowledge on both of these topics, describe the anatomic basis for color vision, and discuss color vision deficiencies. Color vision disturbances can not only interfere with everyday activities but also impede performing specific professions. Commercial or military pilots, electricians, defense forces including paramilitary, food and art critics, and some physicians, scientists, and engineers may not be able to perform their professions to the full extent. Colors play an important role in the culture of various societies. The same color can have the opposite meaning in different cultures. Lack of knowledge of these meanings, when overcoming huge distances, is no longer a problem, but it can lead to unpleasant misunderstandings. Such cultural meanings of color are also discussed.