This book is a resource to enable scholars and students in Yeats studies to explore the materials in his library, which, together with his unpublished papers and manuscripts, forms part of the writer’s archive in the National Library. Generally, this first volume describes the evidence that he and his wife, George, left in books by other authors, including extensive indications of close reading and thinking on a surprising range of subjects. This book could not have been written without the generous participation of the Yeats family over many years. Their legacy, now entrusted to the National Library, is robust and endless in potential. This book is about individual cases but also the building of an oeuvre. In short, this book enriches our understanding of Yeats’s accomplishment as a writer in over fifty years of creative effort and nearly seventy-four years of abundant life.