Official documentation IBM Redbooks for z/OS. z/OS Internet Library contains links to all kinds of z/OS related documentation. zFavorites - another website that stores many z/OS related links in one place. z/OS V2R2 Elements and Features - official z/OS 2.2 documentation in PDF format. z/OS V2R2 Elements and Features - online version of the same documents as above. MVS Shelves - documentation grouped in many useful categories. "Search Documents" function enables you to search content of all documents on the shelf. Shelf: z/OS V1R13 Base Elements and Optional Features - one of the most useful shelf. Richer that shelves related to newer z/OS versions. Shelf: z/OS V2R1 Messages and Codes. Shelf: z/OS V2R1 Commands. LookAt for z/OS - Message search - not the richest resource related to messages, but easy to use. IBM Interactive Product Catalog - 3D models of IBM hardware. PCOMM Macros - documentation describing PCOMM libraries for VBS language.