Rexx is used as a command language for operating, dialog, network systems and database management; as a scripting language for automating and integrating applications in these systems and as a macro language for arbitrary application programs. For example, possibilities of the Rexx language in the environment of OS/400 are described in From Rexx to AS/400. Rexx is a portable language across platforms. For a proof look at links in Hall of fame. In Introduction I would like to show that Rexx is an interesting high-level programming language, too. This is an original introduction. I concentrate only on features of the language Rexx which are not included, in whole, in the others programming languages: arithmetic operations, work with words, the interpret instruction, the SOURCELINE function, multiple exits, associative and sparse arrays. I explain a further wonder in third part of the article From Rexx to AS/400: i. e. External data queue. We can't imagine numbers with a gigantic number of digits; we can't use these numbers. Hence I included in Arithmetic operations the complete explanation of the arithmetic operations in the Rexx language. It is a good idea consider in the course of a solution of a numeric task that "Rexx computes in the same way as we do". Instructions do-(iterate, leave)-end, numeric, interpret, parse, built-in functions, compound variables, recursion,

allow complex algorithms to be expressed in simple programs. I think that Rexx is suitable for learning and teaching programming, compiler construction, mathematic theory of computation (look at my simple implementation of the universal Turing machine). Album of Algorithms & Techniques proves that Rexx is the suitable vehicle for writing a set of routines translating from excellent algorithms texts in clean, succint, uniformly, and tested code. I use Rexx as an ideal environment for design and testing algorithms as in my article comparing FIND SELECT and MODIFIND algorithms. Interpret of the Rexx language is a part of every IBM's operating system. But in Internet you can obtain quite free interprets for almost every operating system, see Hall of Fame. There are links to free source codes, packages, utilities, newsletter, newsgroups, manuals and interesting informations, too. Note to the design of my Rexx page. John Dvorak in his article Get Rexx — It Pays wrote: "... it's apparent that Rexx is something of a Swiss Army knife among programming languages". e-zine OS/2.cz published my article Rexx - language for Robinsons (only in Czech). It is Hall of Fame written for popularisation of the Rexx language in the Czech republic. OS/2.cz included informations from my Rexx page on its CD-ROM.