In How to Build a Billion Dollar App, serial tech entrepreneur George Berkowski gives you exclusive access to the secrets behind the success of the select group of purely mobile app based companies that have achieved billion-dollar success, including two Finnish gaming companies SuperCell and Rovio.
This is a good business that focus on the world of mobile apps. It is useful, even though your goal would not be on billion dollars, but more modest numbers. If you are planning to have a company where your product is a mobile app, this is probably a good read.
Anyone interested in mobile app business.