About the book (from Wikipedia):
On the Genealogy of Morality: A Polemic is a 1887 book by German philosopher Friedrich Nietzsche. It consists of a preface and three interrelated essays that expand and follow through on doctrines Nietzsche sketched out in Beyond Good and Evil (1886). The three Abhandlungen trace episodes in the evolution of moral concepts with a view to undermining “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.