An important prerequisite to the long-term use of nuclear energy is information on uranium ore deposits from which uranium can be economically exploited. Hence the basic purpose of this book is to present an overview of uranium geology, data characteristic for uranium deposits, and a synthesis of these data in the form of a typological classification of uranium deposits supported by more detailed descriptions of selected uranium districts and deposits. An additional goal is to provide access for the interested reader to the voluminous literature on uranium geology. Therefore a register of bibliography as global as possible, extending beyond the immediate need for this book, is provided. The volume presented here was not originally designed as a product for its own sake. It evolved as a by-product during decades of active uranium exploration and was compiled thanks to a request by the Springer Publishing Company. Routine research work on identifying characteristic features and recognition criteria of uranium deposits, combined with associated modeling of types of deposits for reapplication in exploration, provided the data bank. The publisher originally asked for a book on uranium deposits structured as a combined text- and reference book. The efforts to condense all the text into a single publication were soon doomed. The material grew out of all feasible proportions for a book of acceptable size and price, a wealth of data on uranium geology and related geosciences having become available during the past decade, too vast for one volume.