Professor Hans Rademacher was invited by the Mathematical Association of America to deliver the Earle Raymond Hedrick lectures at the 1963 summer meeting in Boulder, Colorado. Professor Rademacher chose the topic Dedekind Sums, and prepared a set of notes from which to deliver the lectures. However, a temporary illness prevented him from giving the lectures, and he prevailed upon his colleague and former student, Emil Grosswald, to make the presentation from the notes.

Professor Rademacher never edited for publication the notes he had prepared for the Hedrick lectures. However, after his death in 1969, the manuscript was found among his papers, with a signed request that Emil Grosswald edit and publish these lecture notes. Professor Grosswald responded affirmatively, and completed the editing of these somewhat fragmentary notes, which consisted of 45 hand-written pages and a sketch of a bibliography. In view of the extensive additions of proofs, historical remarks, and subsequent developments of the subject, made by Emil Grosswald, the Subcommittee on Carus Monographs of the Committee on Publications concluded that joint authorship of the finished monograph was appropriate. The Association is indebted to Professor Grosswald for his dedication in bringing this volume into print.