ABSTRACT
This chapter provides an overview to the nature and documented history of light, which dates back as far as 3000 years ago when the Greeks initiated tentative ideas on the reflection of light from metal surfaces. It includes definitions to a host of quantities that together comprise the basis for the theory of numerous phenomena embraced by the first two phases of study, geometric and physical optics. Whenever possible, an attempt will be made to spell out the connection between each quantity and the part of optics to which it is linked.
