To my surprise, this book is by the founder of IMVU, a virtual world company that is still around from that last virtual world craze back around 2010 (including a company I worked for that didn't make it more than a few years), so it's interesting to read about the progression of that company and does give this methodology some cred. Although the anecdotes are interesting, they are varnished with that rah rah Silicon Valley sheen (the glowing treatment of companies like Facebook seem dated now), and it's easy to poke holes, e.g. lots of pro-pivot talk here, but personally I've been in a lot of places that just pivoted as a symptom of attention deficit and chasing the shiny new toy. But plenty makes sense, like deplying Minimum Viable Products, which as with with many other methodologies is typically distorted into whatever people want to release. Which is why I realize now people going on about MVPs probably didn't read this book, and why you should.