This volume contains 11 lectures delivered by the author 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. The early differential and integral calculus, Christiaan Huygens, and the concept of construction in 17th- and 18th-century mathematics are the three themes around which much of his research has concentrated. Those who teach mathematics, as well as mathematics historians, should appreciate this insightful, wide ranging book.