Henry Pierce Stapp is a senior physicist at the Lawrence Berkeley Laboratory at the University of California, Berkeley, who, in the course of a half-century career in science, has made major contributions to our understanding of quantum theory. A graduate of the University of Michigan, he wrote his doctoral thesis under the direction of the Nobel laureates Emilio Segre and Owen Chamberlain, and earned a Ph.D. in physics from Berkeley in 1955. His dissertation provided a theoretical framework for the analysis of the scattering of polarized protons on polarized targets, which he subsequently used to analyze data, obtained from experiments being conducted at Berkeley’s Lawrence Radiation Laboratory, in the first large-scale computer analysis in high energy physics. In 1957, he accepted the invitation of Wolfgang Pauli to work with him at the Eidgenossiche Technische Hochschule in Zurich on fundamental problems in quantum theory. An essay he wrote then on “Mind, Matter, and Quantum Mechanics” was developed into a book of the same title, which was published thirty-five years later by Springer-Verlag. Dr. Stapp was named to his present position at Berkeley in 1962, and during the sixties, he was a principal mathematical and philosophical spearhead for the then new approach to quantum theory known as S-matrix theory. He proved, within the S-matrix framework, two basic theorems in elementary particle physics and an array of fundamental discontinuity equations. His thesis work on spin-correlation experiments led to intense involvement with Einstein-Podolsky-Rosen non-locality and to a large set of extensions of Bell’s famous non-locality theory. As a visiting scientist, he worked in Munich at the Max-Planck Institute with Werner Heisenberg and at the University of Texas, Austin, with John Wheeler. His 1972 paper “The Copenhagen Interpretation” is widely recognized as a seminal work on the subject. Dr. Stapp’s latest research focuses on the possible strong influence of quantum processes on the human brain, specifically on how the quantum Zeno effect can account for the ability of a person’s conscious choices to causally influence his or her physical actions. He is the author of more than three hundred scientific papers, and, in recent years, he has written and lectured extensively on the social impact of such a revised understanding of the nature of human agency.