Stephen B. Klein is professor in the psychology department at Mississippi State University. He received a B.S. degree in psychology in 1968 from Virginia Polytechnic Institute and a Ph.D. degree in psychology in 1971 from Rutgers University. Professor Klein taught at Old Dominion University for twelve years and at Fort Hays State University for seven years prior to coming to Mississippi State University in 1990. He also served as head of the psychology department at both Mississippi State University and Fort Hays State University. Professor Klein has written numerous articles for psychological journals in the area of the biological basis of learning and memory and is the author of Motivation: Biosocial Approaches, published by McGraw-Hill in 1982; Learning: Principles and Applications, published by McGraw-Hill in 1987, 1991, 1996, and 2002; Learning: Principles and Applications published by Sage in 2009, 2012, and 2015, and Biological Psychology, published by Prentice-Hall in 2000. Dr. Klein also coauthored with B. Michael Thorne Biological Psychology, published by Worth in 2007 and coedited with Robert Mowrer the two-volume text Contemporary Learning Theories in 1989 and Handbook of Contemporary Learning Theories in 2001, both published by Lawrence Erlbaum. His family includes his wife, Marie, and five children, Dora, David, Jason, Katherine, and William. In his spare time, he enjoys sports, most passionately baseball, and science fiction, especially Star Trek and Star Wars.