 The Syntax is probably Carnap’s best-known book, and has attracted much of the renewed attention to Carnap in recent years. At the time of its publication, the Vienna Circle was disintegrating, its members were fleeing from political persecution, and philosophical communication was disrupted. Its English translation, published 1937, lacked context and was almost uniformly misunderstood by nearly everyone, with the partial exception of Quine, whose later work in logic, the philosophy of logic, and logic-based philosophy was inspired by—though sometimes opposed to—the Logical Syntax. Through Quine, some of Carnap’s ideas eventually also found their way into the logic education of many philosophy departments in the US. On the other hand, what Quine understood, as is evident from his 1934 Harvard Lectures, immediately after the book’s publication (reprinted in Creath 1990), was the first draft of the Logical Syntax, in which the principle of tolerance was still absent. So even his comprehension of the Syntax was partial and one-sided (Creath 1987, Friedman 2006). In any case, the book was widely assumed to have been superseded by the time the translation appeared, now that Carnap had meanwhile embraced semantics and dropped his insistence on the “formal mode of speech” (above,  section 1.3).  Only recently, therefore, has the Syntax come to be appreciated in its full radicalism.