The present status of microprogramming is developed from Wilkes's initial concept of microprogramming to the more recent bit-slice microprogrammable computer components. This tutorial defines basic concepts and gives a simple example of machine language interpretation. Describing the characteristics of microprogrammed machines provides the background for an examination of microprogrammable bit slice microprocessors, the most significant commercial development since the previous survey paper [3]. The descriptions of recent applications of microprogramming indicate the potential for microprogram use in several areas. A substantial bibliography directs the interested reader to details in many aspects of microprogramming.