Charles Peirce is unique in American intellectual history and is of seminal importance for modern thought. As early as 1879, it was predicted in the British journal Mind that Peirce's pragmatism would be "one of the most important of American contributions to philosophy." That prediction, made less than a year after Peirce published his first paper on pragmatism, turned out to be remarkably prescient. Pragmatism has indeed become America's great contribution to philosophy, both as a doctrine and body of theory and as a movement that even today boasts many leading American thinkers. The origin of the pragmatic movement was the classic school of American thought led by the Cambridge philosophers, Peirce, James, and Royce, and the great Chicago pragmatist, John Dewey. Peirce's thought was a touchstone that motivated and guided the independently brilliant thought of the other original pragmatists. As more and more scholars from around the world turn toward America for philosophical inspiration, Peirce is emerging as the central figure of its intellectual heritage.

Peirce's leadership in the pragmatic movement would by itself more than justify whatever attention has been given to his work, but he was much more than just a pragmatist. He was a career scientist who made a number of notable—though not paradigm threatening—contributions to geodesy and metrology. He was a linguist and lexicographer who contributed thousands of definitions to encyclopedias and dictionaries. He was a writer and reviewer who contributed hundreds of reports and reviews to popular magazines and newspapers. He was a psychologist and a historian. And he was, in his own words, first and foremost a logician. He was, in fact, the man who introduced logic as a subject for research in America, and he was responsible for a great deal of "the shape" of logic today.