This book is a timely, comprehensive introduction to cloud computing. The phrase cloud computing, which was almost never used a decade ago, is now part of the standard vocabulary. Millions of people around the world use cloud services, and the numbers are growing rapidly. Even education is being transformed in radical ways by cloud computing in the form of massive open online courses (MOOCs). This book is particularly valuable at this time because the phrase cloud computing covers so many different types of computing services, and the many people participating in conversations about clouds need to be aware of the space that it spans. The introductory material in this book explains the key concepts of cloud computing and is accessible.