Charles S. Peirce (1839-1914) is the founder of the philosophy of pragmatism. His interest in signs and their examination in terms of their practical consequences in action, which forms the starting point of his philosophy, has remained a binding aspect of pragmatic thinking to this day. With this approach, Peirce also became the founder of semiotics and relational logic. His concept of action continues to be a fundamental basis for discussions in action theory. The essay "How to Make Our Ideas Clear," which this volume presents in its original form and in German translation, articulates the crucial arguments that led to the theory of pragmatism. The edition includes an introduction, translation, and a detailed commentary by Klaus Oehler, as well as a new afterword by Edward Craig.