Night vision devices are among the most important law enforcement tools today. But they are expensive, and purchasing decisions must be founded on education and understanding of the relative merits of different types of equipment. A night vision device might best be described as a video camera that is extremely sensitive to light. It comes in two main styles: (1) Goggles, which leave the hands free; (2) Handheld devices, the most popular for law enforcement; they can be set up like binoculars or as a simple unmagnified viewer and most can be easily adapted for use with a film or video camera; and (3) Scopes which are used with rifles. Specifications important to an evaluation of a particular device are: (1) Gain -- how much the brightness is increased by the system before the image reaches the eye; (2) Resolution -- the amount of detail that will be available to the user; and (3) Photo sensitivity -- the ability of the photocathode to convert light to an electron image. The author evaluates the performance of several generations of devices, including some made in Russia.