Teaches RPG IV to AS/400 users and RPG programers, focusing on RPG IV in a practical context and the differences between this version and earlier versions of the language. Overviews RPG IV specifications, examines new features, and presents practical applications, with chapters on database programming, various types of operation codes, arrays and tables, string-handling, and printing. Includes appendices of RPG IV compile listings and error-handling data structures. Annotation c. by Book News, Inc., Portland, Or.