The final part of this book consists of two chapters. Chapter 12 addresses concerns that TensorFlow.js users may have when deploying models into production environments. It discusses best practices that help developers gain higher confidence in model correctness, techniques that make models smaller and help them run more efficiently, and the range of deployment environments that TensorFlow.js models support. Chapter 13 is a summary of the entire book, providing a review of the key concepts, workflows, and techniques.