 Thomas Kuhn's landmark book of 1962, "The Structure of Scientific Revolutions", was first published in a volume of the "International Encyclopedia of Unified Science"—a project begun by logical positivists—and somehow, at last, unified the empirical sciences by freeing them from the physics model, and calling them for assessment in history and sociology.Lacking such heavy use of mathematics and logic's formal language—an approach introduced in the 1920s by the Vienna Circle's Rudolph Carnap—Kuhn's book, powerful and persuasive, was written in natural language open to laypersons.