I first encountered this book in edition 1 as a programer. We were on Edition 2 when I was a project Lead and everyone in my staff was issued a copy. On Edition 3 I was teaching a college course on JCL and had the text changed to this excellent reference. I am now a consultant and just finished a two day seminar to familiarize a group of analysts with their computing environment and the necessary JCL to get things done. I showed them edition 5 and recommended they get a copy. I believe that right now an order for about 12 copies of this tool is being approved. Very simply this continues to be the best overall resource on JCL in print. The additional information on TSO and SMS make it the single most powerful technical resource on the market. I have been in data processing for almost 23 years and have yet to encounter anything better.