# GraphQL-Pi-Book Learn about the tasks and key concepts of GraphQL, how it works, and how to put it into action. Explore the difference between GraphQL and REST APIs, as well as between GraphQL operations and types. Get the skills you need to start querying data, adding mutations and relationships, working with relational data, and running tests. Find out why GraphQL is so flexible and efficient, particularly if you’re working with an existing ASP.NET Web API project. Along the way, try out your new skills with practice challenges in each section. https://www.linkedin.com/learning/asp-dot-net-core-building-a-graphql-api/