In case you haven t realized it, building computer systems is hard. As the complexity of the system gets greater, the task of building the software gets exponentially harder. As in any profession, we can progress only by learning, both from our mistakes and from our successes. This book represents some of this learning written in a form that I hope will help you to learn these lessons quicker than I did, or to communicate to others more effectively than I did before I boiled these patterns down.
