[NTG-context] Returning...need advice on manuals for MKIV

Returning after a long absence... Downloaded a fistful of manuals, concentrating on MKIV. One of these lists commands, and is dated 2012 which is promising. Many of these commands are not included in "Context, The Manual". So is there a manual or guide (or multiples) that expains these new commands? Let me put it a different way. If a person familiar with TeX but not Context wanted to use MKIV what documents beyond "Context the Manual" would that person need to understand and use Context for ordinary documents (like a book on another software project)? I use TexLive 2011 on a Slackware Linux platform. -- John Culleton