Miguel de Unamuno (d. 1936), one of the most influential of modern Spanish writers and thinkers, has been described as Spain’s richest mind of the twentieth century. This book provides a bibliography of the approximately 5,700 books in his private library in Salamanca and includes most of his readings and acquisitions. Also listed are at least 2,000 more books from a personal catalogue kept by Unamuno, which have been collated with the present collection. Since Unamuno read in vast and indiscriminate quantities, an organized approach to his library is essential for determining the full dimensions of his intellectual stimulation. An introductory essay by Mario J. Valdes makes an original contribution to the study of Unamuno by analysing intensively the methodology used in his readings, and relating them to his thought. This source book provides answers to many diverse questions about Unamuno and his works, for example: Which newspapers did Unamuno write in? How interested was he in literature from the United States? Did he read Kierkegaard in Spanish? What about Kant? Did he read Catalan? An appendix correlates the catalogue of readings to the Vergara edition of Unamuno’s Obras completas.