The programming language PASCAL-XSC (PASCAL eXtension for Scientific Computation) significantly simplifies programming in the area of scientific and technical computing. PASCAL-XSC provides a large number of predefined data types with arithmetic operators and predefined functions of highestaccuracy for real and complex numbers, for real and complex intervals, and for the corresponding vectors and matrices. Thus PASCAL-XSC makes the computer more powerful concerning the arithmetic. Through an implementation in C, compilers for PASCAL-XSC are available for a large variety of computers such as personal computers, workstations, mainframes, and supercomputers. PASCAL-XSC provides a module concept, an operator concept, functions and operators with general result type, overloading of functions, procedures, and operators, dynamic arrays, access to subarrays, rounding control by the user, and accurate evaluation of expressions. The language is particularly suited for the development of numerical algorithms that deliver highly accurate and automatically verified results. A number of problem-solving routines with automatic resultverification have already been implemented. PASCAL-XSC contains Standard PASCAL. It is immediately usable by PASCAL programmers. PASCAL-XSC is easy to learn and ideal for programming education. The book can be used as a textbook for lectures on computer programming. It contains a major chapter with sample programs, exercises, and solutions. A complete set of syntax diagrams, detailed tables, and indices complete the book.