The essays and commentaries presented here are intended to strike a balance between the disciplines to which the Bar-Hillel Colloquium (formerly the Israel Colloquium) is dedicated. The historical and sociological vantage point is addressed in Krammick's and Mali's treatment of Priestley, in Vicker's and Feldhay's studies of the Renaissance occult and in Warnke's and Barasch's work on the imagination. From a philosophical angle several concepts, all material to the methodology of science, are taken up: rule following, by Smart and Margalit; analysis, by Ackerman, explanation, by Taylor; and the role of mathematics in physics, by Levy-Leblond and Pitowsky. In addition, the volume contains the proceedings of two symposia dedicated to two towering scientific figures: one celebrates Bohr's centennial, and the other examines the "other" Newton. The book should appeal to people whose interest or research is in the fields of philosophy, sociology and history of science, technology and medicine, as well as those interested in science education.