This book is based on Laravel 5.1 version, introduces the principles of Laravel construction from the perspective of framework technology, and introduces the application of Laravel functions from the source code level. By studying this book, readers can understand all aspects of the implementation of the Laravel framework and complete the development of customized applications based on the framework. Chapters 1 to 4 of this book mainly introduce the basic parts related to learning the Laravel framework. Readers can have an in-depth understanding of the design ideas of the framework, build a learning environment, and understand PHP syntax knowledge and HTTP protocol; Chapter 5 to Chapter 14 It introduces how the Laravel framework is built and used from a certain aspect, including the program life cycle, service containers and databases, etc., and also separates some of the construction technologies so that readers can learn the construction technologies and ideas of the framework. Such as the content of design patterns; Chapter 15 is a simple example that connects the previous learning content and applies it in practice, so that readers can learn to use this framework to customize applications. This book is suitable for readers who want to understand the Laravel framework construction technology, as well as readers who want to understand the Laravel framework in depth.