Simply to say that this is a collection of essays in honor of the late Wolfgang Yourgrau (1908-1979) is to explain, at least for-the obviously many-"insiders," the unusually wide-ranging title of the present volume. In a Foreword to the Proceedings of the First International Colloquium (focusing on logic, physical reality, and history), held at the University of Denver in May of 1966 under their leadership, Wolfgang Y ourgrau and Allen Breck wrote, in an oblique reference to C. P. Snow: "Indeed there are not two or three or four cultures: there is only one culture; our generation has lost its awareness of this . . . . Historians, logicians, physicists-all are banded in one common enterprise, namely in their des ire to weave an enlightened fabric of human knowledge. " Augment, if you will, the foregoing categories of scholars with biologists, philos­ ophers, cosmologists, and theologians-all of whom, in addition to historians, Wolf­ gang Yourgrau, by dint of his inextinguishable enthusiasm and charismatic qualities, assembled in Denver for the Second and Third International Colloquia (in 1967 and 1974, respectively)-and a few other besides, and one arrives at a statement of the credo wh ich Y ourgrau not only professed, but consistently exemplified throughout his adult life.