"The Genealogy of Morals" traces the episodes in the evolution of moral concepts with a view to confront «moral prejudices», specifically those of Christianity and Judaism. Some Nietzsche scholars consider Genealogy to be a work of sustained brilliance and power as well as his masterpiece. Since its publication, it has influenced many authors and philosophers. "Ecce Homo: How One Becomes What One Is" is the last book written by Nietzsche before his final years of insanity that lasted until his death in 1900. According to Walter Kaufmann, Nietzsche's most prominent English translators, the book offers «Nietzsche's own interpretation of his development, his works, and his significance.» "Selected Letters" includes various personal letters by Nietzsche to his family and friends. Friedrich Nietzsche (1844–1900) was a German philosopher, poet, and Latin and Greek scholar whose work has exerted a profound influence on Western philosophy and modern intellectual history. Because of Nietzsche's evocative style and provocative ideas, his philosophy generates passionate reactions. His works remain controversial, due to varying interpretations and misinterpretations of his work. In the Western philosophy tradition, Nietzsche's writings have been described as the unique case of free revolutionary thought, that is, revolutionary in its structure and problems, although not tied to any revolutionary project.