'[These lectures] are about themes of the history of mathematics which, for various reasons, are dear to me. The early differential and integral calculus, the work of Christiaan Huygens, and the concept of construction in seventeenth and eighteenth-century mathematics are the three themes around which much of my research has concentrated and which continue to fascinate me by the insights they offer in the development of that special human activity called mathematics' - from the Introduction. This volume contains eleven lectures ranging over a variety of topics in the history of mathematics. The lectures, presented between 1970 and 1987, were delivered in a variety of venues and appeared only in less accessible publications. Those who teach mathematics, as well as mathematics historians, will appreciate this insightful, wide-ranging book.