The popularity of Pascal as a teaching language has rapidly increased, as demonstrated by Addyman's survey conducted over a11 European and American institutions (Comput. Bull., Se ries 2,8, June 1976,31). This is due both to the desirable features of the language and to the ease of producing an efficient com piler. As an instance of the latter, the authors have investigated the full CDC CYBER compiler and found it to throughput at 1.8 times the rate of the manu facturer's Fortran compiler. These features of the language and compilers have also been favourably regarded by system programmers and users of rnicroprocessors. In the latter field, it is the belief of the authors that Pascal will supersede the programming language BASIC. Specifically, undergraduates in the Department of Computer Science at Manchester University program largely in Pascal. An introductory le~ture course on basic programming techniques, given at Manchester, has been taken as a basis for this book. In addition to lectures, the course consists of two kinds of practical session. The first is based on the solution of short pencil-and-paper exercises. The second requires the student to write complete programs and run them in an 'edit and go' mode on interactive computer terminals. Each chapter of the book conc1udes with exercises and problems suitable for these purposes. Although solutions to a11 of these are not presented in the book, teaching staff may obtain them by application to the authors.