This is a relief. Though, of course, as the author of the book I must claim deep expertise in the subject matter, Simmons has forgotten more about UserLand products than I know. The odds that this book will be a disgrace to my good name and that of the UserLand community just went down considerably.
A couple of years back a chapter/case study I'd written about a pretty deep API ended up being reviewed by the bloke who wrote most of the code. Pages and pages of heavy crit, nearly had me in tears. But the end result was undoubtedly a vast improvement on what it would have been otherwise, and everyone lived happily ever after ;-)
In the case of Rogers' book, I'm happy to report that there are not "pages and pages of heavy crit," just a few little things here and there. Nits mostly.