My interest in and appreciation for program evaluation began in the early 1970's when conducting a curriculum development research project at the University of Florida's P. K. Y onge Laboratory School. This interest was sparked when it became apparent that testing the success of an education program required more skills than just statistics and research methods. After pursuing additional formal schooling, I embarked on a career featuring educational program evaluation as its central thrust--as a private consultant, later in a university health sciences center involving seven academic colleges, and then in the Cooperative Extension Services of Florida and Maryland. Adding evaluability assessment (EA) to the performance of evaluations, to program development, and to teaching about evaluation has been a significant development for me personally, and I hope to those who have been participants with me in each endeavor. This book grew out of many of these experiences and involved numerous colleagues who made significant contributions. First among these is Dr. George Mayeske, Program Evaluation Specialist, Extension Service, U. S. Department of Agriculture, Washington, D. c.