For many years Professor James C. I. Dooge was invited to the IHE in Delft to present a short series of lectures (1968-1981) on Deterministic Hydrology to IHE's International Course for Hydrologists. This book is largely based on the lecture notes he used. In 1992 Professor Dooge was made an Honorary Fellow of IHE. Subsequently, Professor J. Philip O'Kane delivered the lectures to the international students attending what is now known as the Master Programme in Hydrology and Water Resources. He is the author of the PICOMO program that accompanies the book. The software is downloadable from the IHE website. Both authors have worked together to revise and extend the text for publication.