This book was written for several audiences. Our first audience is application development managers that need to deliver software to production in short development cycles while mitigating the inherent risks of software development. Our second audience is the software development community at large. To them, this book sends a profound message: Scrum represents a new, more accurate way of doing software development that Is based on the assumption that software is a new product every time that it is written or composed. Once this assumption is understood and accepted, it is easy to arrive at the conclusion that software requires a great deal of research and creativity, and the therefore it is better served by a new set of practices that generate a self-organizing structure while simultaneously reducing risk and uncertainty. Finally, we have also written this book for a general audience that includes everyone involved in a project where there is constant change and unpredictable events. For this audience Scrum provides a general-purpose project management system that delivers, while it thrives on change and adapts to unpredictable events. Software as "new product" as presented in this book, is radically different from software as "manufactured product", the standard model made for software development throughout the last 20 years.

Manufacture-like software methods assume that predictability comes from defined and repeatable processes, organizations, and development roles; while Scrum assumes the process, the organization, and the development roles are emergent but statistically predictable, and that they arise from applying simple practices, patterns and rules. Scrum is in fact much more predictable and effective than manufacturing-like processes, because when the Scrum practices, patterns and rules are applied diligently, the outcome is always; 1) higher productivity, 2) higher adaptability, 3) less risk and uncertainty, and 4) greater human comfort. The case studies we provide in this book will show that Scrum doesn't provide marginal productivity gains like process improvements that yield 5-25% efficiencies. When we say Scrum provides higher productivity, we often mean several orders of magnitude higher i.e. several 100 percents higher. When we say higher adaptability, we mean coping with radical change. In some case studies, we present cases where software projects morphed from simple applications in a single domain to complex applications across multiple domains: Scrum still managed while providing greater human comfort to everyone involved.

Finally, we show through case studies that Scrum reduces risk and uncertainty by making everything visible early and often to all the people involved and by allowing adjustments to be made as early as possible. Throughout this book we provide 3 basic things: 1) an understanding of why this new thinking of software as new product development is necessary, 2) a thorough description of the Scrum practices that match this new way of thinking with plenty of examples, and 3) a large amount of end-to-end case studies that show how a wide range of people and projects have been successful using Scrum for the last 6 years. This last point is our most compelling argument: The success of Scrum is overwhelming. Scrum has produced by now billions of dollars in operating software in domains as varied as finance, trading, banking, telecommunications, benefits management, healthcare, insurance, e-commerce, manufacturing and even scientific environments. It is our hope that you, the reader of this book, will also enjoy the benefits of Scrum, whether as a development staff member wishing to work in a more predictable, more comforting, and higher producing environment, or as a manager desiring to finally bring certainty to software development in your organization. Mike Beedle, Chicago Ken Schwaber, Boston.