The formal sciences, particularly mathematics, have had a profound influence on the development of linguistics. This insightful overview looks at techniques that were introduced in the fields of mathematics, logic and philosophy during the twentieth century, and explores their effect on the work of various linguists. In particular, it discusses the 'foundations crisis' that destabilised mathematics at the start of the twentieth century, the numerous related movements which sought to respond to this crisis, and how they influenced the development of syntactic theory in the 1950s. The book concludes by discussing the resulting major consequences for current syntactic theory, and provides a groundbreaking and detailed reassessment of Chomsky's early work at the advent of Generative Grammar. Informative and revealing, this book will be invaluable to all those working in formal linguistics, in particular those interested in its history and development.