The history of psychology is fascinating, both for the complexity of the path it had to follow to establish itself as a science and for the significant contributions psychologists have made to contemporary culture and our understanding of ourselves. This book recounts this history in detail, divided into three parts.The first part, Foundations, provides essential insights into science and describes the most relevant philosophical currents that contributed to the establishment or understanding of psychology. The second part, The Foundation of Scientific Psychology (19th-20th centuries), details the foundational period when psychology broke away from philosophy and became an autonomous science through the use of the experimental scientific method. Finally, the third part, Psychological Schools (20th century), describes the origins and characteristics of the main psychological approaches: functionalism, structuralism, behaviourism and behaviourism, Gestalt psychology, psychoanalysis, humanistic psychology, and cognitive psychology.This is a comprehensive and clear text, drawing on the author's teaching experience, which will interest not only psychology students but also anyone who wants to understand the basic theories of the main psychologists and schools of thought.