From the Preface: “Primarily this book is intended for application of the operational calculus to mathematics, physics and technical problems. We have therefore given not only the basic principles, ideas and theorems as clearly as possible (and rather extensively), but also many worked-out problems from purely mathematical and physical as well as from technical fields ... [S]ome of the deeper theorems have been omitted, and for these the reader is referred to the mathematical literature ... Nonetheless, it is believed that the purely mathematical treatment is more advanced than is usual in books devoted primarily to practical applications ... It is therefore hoped that the book may be of value to those pure mathematicians who are interested in a rapid and simple derivation of complicated and unexpected relations between various mathematical functions, as well as to the engineer in search, for example, of a very simple treatment of transient phenomena in electrical networks, such as filters. In both cases the operational calculus appears to its best advantage.”