Walter Kauzmann came to Princeton in 1946 to replace his former mentor, Henry Eyring, who went back to Salt Lake City and his Mormon roots. He has written about his reminiscences in physical chemistry, proteins, and related topics in Protein Science,1 and a special issue of Biophysical Chemistry has been published containing tributes of his many students and admirers.2 These sources, together with his published work and our own personal experiences, have provided the material for this tribute and review. In his early days, WK was at once shy and modest and a wondrous communicator. The simplicity of his laboratory–office, where this communication took place, has already been described.3 His reputation for “knowing everything” was quickly perceived by students, faculty members, and visitors. There were no limits on subject matter. Sometimes discussions involved a blistering array of quantum mechanical or statistical mechanical formulas; at other times quite basic ideas for beginning students, for example, partition coefficients or elementary discussions of the entropy. The range of topics was very large and went from mathematical science, to history, geology, paleontology, and many others. A major part of learning in these early days came from observing how a real scientist worked and thought. In the first 5 years (1946–1951), there were at least 10 students and two postdocs associated with the laboratory. Clearly, they did not fit in his small space and most spent much of their time either in the library, their rooms, or at instruments outside the laboratory, for example, the polarimeter. He was not especially solicitous with his students. You had to have something to say to get his attention. (There is a small percentage of disgruntled students.) A disagreement or a misconception on our part was especially effective as a conversation starter. His trips to the Carlsberg laboratory in Copenhagen, where science and fun were mixed in a very natural way, made a lasting impression on him.1 After returning from his first trip, he spent less time in his office, adopted an interest in tennis, not discussed, but obvious to his laboratory mates, and signs appeared of a lady in his life, Elizabeth Flagler, who was to become his wife in 1951. His life was a very busy one outside of his research. One of his constant lines of interest was the structure and thermodynamics of water. Also, he published a book with David Eisenberg on water and extensive papers with Kuntz and Henn (see section on Water). He was avidly interested in his courses including those for undergraduates. A result of this interest was the publication of two excellent books4,5 at the undergraduate or beginning graduate level and one at the graduate level on quantum mechanics.6