Manufacturing test of microelectronics integrated circuits and products based thereon has now become one of the most challenging problems facing the semiconductor industry. There are several fundamental challenges such as potential yield loss due to tester accuracy relative to the devices being tested; exponentially increasing cost of new testers; and a lack of effective and viable means for failure analysis. All of these problems have been described very eloquently by the two previous keynote addresses at VTS.This talk will explore the solution needed for these problems. The concept of embedded test will be described in detail with its applicability to real ICs and products. Also explored will be the business impact of embedded test and why it must live together with external test to provide the best solution for many years to come. This combination of embedded and external tests will be seen as the most critical development of the microelectronics test industry.