Excerpt from a book titled "Getting started with FastAPI 2023". The book acts as a guide for developers to learn and understand how to create web applications with the FastAPI framework. It covers fundamental concepts like setting up the development environment, building APIs, interacting with databases, and using templating engines. The text focuses on explaining how to build CRUD operations for a task management application, showcasing best practices and advanced features of the framework. The author also provides code examples and explains the implementation of testing strategies, including unit testing and integration testing with pytest.