In this book, James argues that the most important criterion for evaluating ideas and beliefs is their practical usefulness in real-life situations, rather than their abstract truth or correspondence to reality. James introduces the concept of "pragmatism," which he defines as a method of approaching philosophical questions by examining their practical consequences. He argues that truth is not an absolute and fixed entity, but rather a relative and changing one that is determined by the practical outcomes of our beliefs and actions. Read in English, unabridged.