Literate programming is a methodology that combines a programming language with a documentation language, thereby making programs more robust, more portable, more easily maintained, and arguably more fun to write than programs that are written only in a high-level language. The main idea is to treat a program as a piece of literature, addressed to human beings rather than to a computer. The program is also viewed as a hypertext document, rather like the World Wide Web. (Indeed, I used the word WEB for this purpose long before CERN grabbed it!) This book is an anthology of essays including my early papers on related topics such as structured programming, as well as the article in The Computer Journal that launched Literate Programming itself. The articles have been revised, extended, and brought up to date.