This is the best book on ISPF I have ever used, including the IBM manuals as far as developing ISPF applications with REXX or CLIST. Other ISPF books contain pages and pages of screen prints you could simply see for yourself on the computer. Practical usage of ISPF showed me quickly and easily how to use ISPF skeletons, tables , and ISPF library management services within an application. These are features that are so poorly explained in the manuals I could not implement then until I read this book. It does assume you know some basics of ISPF, but it is an excellent bridge from the basics to more advanced topics.