In fact I could only dream about writing this book while working full time at Microsoft. I had problems finding time to share experiences with other teams working on the same project. We were all too busy writing software. And then I managed to get a four-month leave of absence. This is how this book started. Teaching courses to a live, demanding audience is the best way of systematizing and testing ideas and making fast progress writing a book. The goal I put forward for the courses was to prepare the students for jobs in the industry.