This new edition of the definitive Pascal reference updates the text with the most recent revisions of the ISO Pascal standard, performed by Working Group 2 of the ISO community, since the standard was formally ap- proved in 1983. This reversion of the ISO standard resolved differences between it and the American (ANSI) standard, and these as well as other changes are subsequently reflected in this new edition. It should be noted that in 1984 the third edition of this book was modified with respect to the standard while retaining the readability and elegance which originally set it apart from the standard. This book consists of two parts: The User Manual, and the Revised Report. The User Manual is directed to those who have some familiarity with computer programming, and who wish to get acquainted with the language Pascal. The style of the User Manual is that of a tutorial, and many examples are included to demonstrate the various features of Pascal. Summarizing tables and syntax specifications are among the Appendices. The Report serves as the ultimate, concise reference for both programmers and implementors. It describes Standard Pascal which constitutes a common base between various implementations of the language.