Free Prize Inside is Seth Godin's followup to Purple Cow. Purple Cow's thesis was that marketing should rely on a truly extraordinary product that speaks for itself, rather than the hopes and dreams of a large advertising budget.
I enjoyed Free Prize Inside. Funnily enough, I picked it up at a used bookstore in Chicago back in college years ago because of its unique cover. The book sells itself as the how-to guide sequel to Purple Cow. A purple cow, in short, is a product that to some degree is inherently controversial. An inherently controversial product is, well, going to lead to some degree of friction in your company. With that, the "how-to" guide is less of a how to lead an R&D team (R&D, usability tests, and focus groups actually being something that Seth warns against), but how-to manage upwards and pitch your company through one rung of management at a time. Seth even goes into the nuances of finding a patron executive or where to use Powerpoint. For this reason, the last 3rd of the book was the most interesting personally. Nevertheless, I still found myself fast forwarding through more anecdotal "proof" as examples.
TL;DR: Great follow-up and Purple Cow + Free Prize Inside is a decent towfer for anyone looking to get back to first marketing principles and get a few ideas.