Crush it tells the story of a very successful man that turned his Dad's wine business in to a financial success story and how you can ditch the job and make a living enjoying your passion.
It's upbeat, inspirational, spicy, believable with a few words of warning thrown in for good measure for anyone that says it doesn't work for them.
Out of self help books I would say it's certainly one of the better types, love your family, work hard, focus on doing what you love to do. Pretty standard fayre.
It can certainly help some that want to make that break, but others, those that enjoy their passions because it's a break from the day job, maybe not so much.
Lots of people have hobbies because they are hobbies. The possibility of feeling obligated to do your hobby as a means to an end, rather than simply for it's own sake, has the potential to kill off the enjoyment gained from it in the first place.
Overall it is a method that worked for Gary and may well work for others too. Saying that, there are lots of biographies of very successful people and in the main, they all got there by being passionate about what they do.
This is just that formula in a popularised format, nothing wrong with that, but I find with these types of books people get off to a great start, then fizzle out, regardless of the authors warning of hard work ahead.