This looks like a book worth having if you really need to understand how to deal with Oracle's CBO.
Nothing on Amazon or the Apress website yet so I don't know the price. Unfortunately, there isn't an indication of size either. The optimizer is one of those subjects which could, if demonstrations and detailed analysis is shown, easily run to a thousand pages. While that information is valuable, it also puts up the cost and hence the price, which will limit its affordability. Hopefully any such detail has been consigned to the zip-file of scripts mentioned.
The technical reviewers were Wolfgang Breitling and Christian Antognini. While I hadn't previously encountered any of Christian's work, I followed the links and found one of his presentations and it's worth a read. I've referred to Wolfgang's work in my post on 10053 and judging by previous papers, I'd be confident that anything he had technically reviewed would be sound.
I do like the teaser in the preface - "The preface exists to tell you what’s not in Volume 1.".