Very worthwhile purchase. Addresses the big problems developers have with business - primarily the fact we tend to build software before finding out if anyone is prepared to pay for it, but also other things such as our tendency to want to spend days writing scripts to automate tasks that we could just pay someone to do in a couple of hours.Walling promises at the very start of the book that you'll be making notes all the way through. Well I'm glad I bought the Kindle edition because I did just that, and the sections I highlighted read like a todo list for a one-man startup.Unlike some others in this space, he doesn't waste your time with rambling anecdotes about cool dudes making millions running startups out of Thai beach shacks. He manages expectations and - rare for a book of this nature - actually uses hard numbers when talking about pricing, conversion rates and income. A very refreshing and inspiring read.