Techniques and Insights to Deliver High-Quality, Maintainable Code Test-Driven Development (TDD) is not only a way to test your code but a complete method of crafting software: How you think about code, the act of writing code, and how you continuously interact with your team's code. Essential Test-Driven Development guides you through writing tests before code, ensuring that every feature is clearly specified, thoroughly validated, and ready to meet evolving business needs. This book shows how TDD can transform your development process by reducing costly bugs and empowering your team to deliver value with confidence. You'll see fewer defects with less worry about breaking existing features while implementing new ones. Developers can confidently reshape their code's internal design to accommodate new features and spend less time debugging. The techniques and real-world examples in this book make TDD accessible to developers, managers, and product owners alike. Learn how to create a safety net of automated tests that protect your investment, accelerate delivery, and enable fearless innovation--whether working with legacy systems or new technologies. By adopting a test-driven mindset, you gain the skills to build software that's not only reliable today but is resilient to change tomorrow. Master the core TDD workflow of "Red, Green, Refactor" for iterative, quality-driven development Build and extend behaviors with clear, executable specifications Design for exceptional cases and edge conditions to prevent costly surprises Sustain a healthy, maintainable test suite with proven, long-term strategies Use test doubles to isolate dependencies and keep your tests fast and focused Apply TDD techniques to legacy codebases, making old software testable and reliable Understand the business impact of wholehearted TDD: fewer defects, faster feature delivery, and greater adaptability Explore how TDD principles extend across languages, frameworks, and modern agentic AI development Take a practical step toward fewer bugs and smoother releases by exploring TDD at your own pace, with targeted examples and guidance you can actually use. Register your book for convenient access to downloads, updates, and/or corrections as they become available. See inside book for details.