"The Genealogy of Morals" (Original German Title "Zur Genealogie der Moral: Eine Streitschrift') is a seminal work in which Nietzsche delves into the historical and psychological origins of moral values, continuing his arguments in Beyond Good and Evil. This book has greatly influenced Modernist thinkers like Sigmund Freud, and Post-Modern thinkers like Michel Foucault. It was very popular in France in the 20th century, further establishing a Nihilistic foundation of central European society. This work, which consists of a preface and three "treatises," is one of Nietzsche's most influential writings. They are not a collection of aphorisms like most of his other works, but longer, systematic texts with a thoroughly scientific approach: he presents sociological, historical, and psychological theses attacking Protestant Theology. Unlike the classical moral philosophers, Nietzsche does not attempt to derive or justify morality, but rather to trace the historical development and psychological preconditions of certain moral values. Thus, he does not ask how people should act, but why people (individuals or groups) believe they should act in a certain way, or want others to act in a certain way. He uses a genealogical method to trace the development of moral concepts, revealing their contingent and power-laden nature. The book is divided into three essays, each exploring different aspects of morality, including the contrast between master and slave morality, the role of guilt and guilt in the formation of conscience, and the ascetic ideal. Nietzsche's analysis in this work has had a profound influence on subsequent philosophical and cultural thought, particularly in the fields of ethics and moral psychology.