This book’s primary focus is on designing hypermedia APIs. That may seem a bit strange to some readers. There are many books on programming languages, data stor- age systems, web frameworks, etc. This is not one of those books. Instead, this book covers the nature of the messages passed between client and server, and how to improve the content and value of those messages. I, personally, find this to be an exciting and fascinating area. how to improve the content and value of those messages. I, personally, find this to be an exciting and fascinating area.