Assembly language provides the link between high-level languages and the physical operation of a computer. This book introduces assembly language programming using either Pentium or RISC processors and either DOS or Linux. It focuses on providing the reader with a firm grasp of the main features of assembly language programming and how it can be used to improve the performance of a computer system. The author's new themes for the revised edition are protected-mode Pentium programming, MIPS assembly language programming, and use of the NASM and SPIM assemblers for a Linux orientation.