This resource library contains various documents and references related to the High Level Assembler for z/OS, z/VM, and z/VSE. It includes installation and customization guides, programmer's guides, and manuals covering topics such as macro language, conditional assembly language, instruction formats, addressing modes, and more. The library also provides information on system variable symbols, data attributes, and special characters used in the assembler language. With a comprehensive collection of resources, this library serves as a valuable reference for programmers and users of the High Level Assembler.