He earned his B.A. degree in statistics, mathematics and sociology from Hebrew University in 1955, an M.Sc. degree in operations research and statistics from the Technion in 1960, and a Ph.D. degree in operations research from Columbia University in 1962. He is perhaps best known for his groundbreaking articles on change-point problems, common mean problems, Bayes sequential strategies and reliability analysis. His lifelong enthusiasm in handling difficult problems arising in science and engineering has been a primary inspiration behind his most important theoretical publications. His studies on survival probabilities in crossing mine fields as well as his contributions in stochastic visibility in random fields are regarded as fundamental work in naval research and other defense related areas. Professor Zacks' authoritative book, The Theory of Statistical Inference (1971), and its 1975 Russian translation have served graduate programs and researchers all over the globe very well for over 30 years. He has written other books and monographs, including Parametric Statistical Inference: Basic Theory and Modern Approaches (1981b), Introduction to Reliability Analysis: Probability Models and Statistical Methods (1992), Prediction Theory for Finite Populations (1992), coauthored with H. Bolfarine, Stochastic Visibility in Random Fields (1994b) and Modern Industrial Statistics: Design and Control of Quality and Reliability (1998), co-authored with R. Kenet. He is the author or co-author of more than 150 research publications. During the period 1957 through 1980, his career path took him to the Technion (