This book is recognized as the standard reference manual for the REXX Programming Language, much as Kernighan and Ritchie is recognized as the standard reference book for the C Programming Language.
REXX is the programming language designed for people, not machines. It swept IBM when it was first distributed on IBM's internal network by its creator. With heavy use by a lively networking community, it has evolved to meet the needs of its users. In 1987, IBM acknowledge its success and adopted it as one of the cross-system SAA (Systems Application Architecture) languages. Now, REXX has spread outside IBM, on both mainframes and micros. Today, more than six million people have REXX on their systems.