Stephen Toulmin's The Uses of Argument distinguishes itself as a work of importance in three different yet related fields. As philosophy it offers a compelling critique of analytic methods for looking at arguments, showing the limitations of a philosophical system that excludes discussion of ethical and practical issues. As rhetorical theory it was, along with Perelman's New Rhetoric, to reinvigorate Aristotle's topics within philosophical and practical argument. As argumentation theory, it models and maps arguments, providing a basic vocabulary for establishing claims, in terms of "warrants," "grounds," and "backing."
Toulmin is a gifted and engaging writer. He often lays out a concept in incomplete form, though, making one wonder exactly what he meant. You have to look at other things he's written much later to see a fuller exposition of an idea that is tantalizing in its original instance. He, for example, discusses "argument field" in Uses of Argument, but provides little explication of the term. You have to read his much later Human Understanding to begin to get a fuller picture of the idea.
Toulmin has often changed directions intellectually, so his work might not universally appeal to someone interested in argument or rhetoric. Nevertheless, his knowledge and writing style make him a consistently entertaining philosophical showman, much in the tradition of Bertrand Russell. He has also written one of the best books ever about Wittgenstein.
He has made significant contributions to epistemology and the philosophy of science.
