This book provides an introduction to six key concepts within philosophy: philosophy itself, language, knowledge, truth, being and the good. At the same time, it aims to initiate its readers into the processes of philosophical thinking. The book is addressed to students and lay persons, but also contains new ideas for specialists. It is written in a clear, accessible and engaging style. The German version appeared in eight editions and the second revised and updated English editon has the potential to become a key textbook for an international audience.