Rexx: Power Through Simplicity (O'ReillyNet)
Rexx was the first widely used scripting language. Though IBM invented it 25 years ago, it may come as a surprise that this language is more popular today than ever. There are now nine free and open source Rexx implementations. These run under virtually any operating system on any platform. All but one meet the Rexx language standard, and each has optimizations or extensions for a specific purpose."
