My experience raises the opposite question: how up to date is Guzziology? I bought my copy (version 8.1) in mid-2013 right after I got my V7 Stone. At this time the single-throttle V7s had been out for almost 2 years (in Europe). The book has nearly nothing on these bikes, even though it was advertised as including them. So, I would conclude that Guzziology is a great resource for restorers and old bike aficionados, but not for the purchaser of new bike who wants guidance on its workings and maintenance.