I. AGILE DEVELOPMENT -- Agile Practices -- Overview of Extreme Programming -- Planning -- Testing -- Refactoring -- A Programming Episode -- II. AGILE DESIGN -- What Is Agile Design? -- SRP: The Single-Responsibility Principle -- OCP: The Open-Closed Principle -- LSP: The Liskov Substitution Principle -- DIP: The Dependency-Inversion Principle -- ISP: The Interface-Segregation Principle -- III. THE PAYROLL CASE STUDY -- Command and Active Object -- Template Method & Strategy: Inheritance vs. Delegation -- Facade and Mediator -- Singleton and Monostate -- Null Object -- The Payroll Case Study: Iteration One Begins -- The Payroll Case Study: Implementation -- IV. PACKAGING THE PAYROLL SYSTEM -- Principles of Package Design -- Factory -- The Payroll Case Study (Part 2) -- V. THE WEATHER STATION CASE STUDY -- Composite -- Observer - Backing into a Pattern -- Abstract Server, Adapter, and Bridge -- Proxy and Stairway to Heaven: Managing Third Party APIs -- Case Study: Weather Station -- VI. THE ETS CASE STUDY -- Visitor -- State -- The ETS Framework.