Professor Harris presents a formal theory of language structure, in which syntax is characterized as an orderly system of departures from random combinations of sounds, words, and indeed of all elements of language. He argues that the combining of words into a sentence constitutes a mathematical object, and that each departure from equiprobability is a contribution both to the structure and to the meaning of a sentence. He discusses the differences in the structure and content of language, mathematics, and music, and shows that the use of language in a science constitutes a distinguishable sub-language. The structure of that sub-language organizes the information in the science and lies between the structure of language and that of mathematics. The syntactic theory developed here throws light upon the structuring of information and upon the nature and development of language, which the author shows to be a self-organizing and evolving system.