The Mathematical Association of America nominated Professor Hans Rademacher as Hedrick Lecturer for the summer meeting of 1963. As topics for these lectures, Professor Rademacher selected the “Dedekind Sums”, a subject to which he had returned many times throughout his long and distinguished career and to which he had contributed immensely.

He prepared a set of notes (called in what follows the “Notes”), but a passing indisposition prevented him from delivering the lectures.

He recovered soon afterwards, was once more active in mathematics and wrote at least seven papers (among which there is also one on Dedekind sums) after 1963, but, for unknown reasons, failed to edit for publication his “Notes” of the Hedrick Lectures.

In September of 1967, Professor Rademacher was stricken by a cruel illness, from which he never recovered. After his death on February 7, 1969, the manuscript was found among his papers; on the first page had been added the following words, in Professor Rademacher's handwriting: “If I should be unable to publish these lectures, I wish to ask Emil Grosswald to edit and publish them, (signed) Hans Rademacher (dated) 8-th September, 1963.”

Having had the privilege to be first Professor Rademacher's student, then, for many years, his colleague at the University of Pennsylvania and — I dare hope at least—his friend, there could be no question on my part about the acceptance of this assignment. This turned out to be more difficult than anticipated.