¿Agile is a Philosophy¿The term agile means ability to move quickly and easily and responding and responding swiftly to change. This is the key aspect of agile software development.The agile practices involve continuous planning, testing, integration and other forms of evolution of the project. At the end of each iteration a working product should be delivered. The iterative and incremental nature of agile will allow you to changes effectively. The customer is considered as an agile team because agile projects include the customer in all of the important activities. Here in this book, the key agile practices are described that might be part of an Agile development initiative at an organization. Book is organized into ten chapters. Chapter 1 is introduction to agile practices while chapter 2 highlights the continuous integration process. Exploratory testing, refactoring, test driven development, incremental design, unit testing, incremental design, spike solutions, exploratory testing, and performance optimization are described from chapter 3 to chapter 10. Reader will be able to understand and explore the agile practices and different roles of XP teams.