Slow and fast light: fundamentals and applications

We review progress in the development of methods for controlling the group velocity of light. These methods allow one to create situations in which the group velocity of light is much smaller than the velocity of light in vacuum c, in which the group velocity is greater than c, or in which the group velocity is negative. We present a survey of methods for establishing extreme values of the group velocity, concentrating especially on methods that can work in room temperature solids. We also describe some of the applications of slow and fast light that are currently under development.