This book examines mathematical discourse from the perspective of Michael Halliday's social semiotic theory. In this approach, mathematics is conceptualized as a multisemiotic discourse involving language, visual images and symbolism. The book discusses the evolution of the semiotics of mathematical discourse, and then, proceeds to examine the grammar of mathematical symbolism, the grammar of mathematical visual images, intersemiosis between language, visual images and symbolism and the subsequent ways in which mathematics orders reality. The focus of this investigation is written mathematical texts. The aims of the book are to understand the semantic realm of mathematics and to appreciate the metaphorical expansions and simultaneous limitations of meaning in mathematical discourse. The book is intended for linguists, semioticians, social scientists and those interested in mathematics and science education. In addition, the close study of the multisemiotic mature of mathematics has implications for other studies adopting a social semiotic approach to multimodality.