Hypertext Transfer Protocol (HTTP) is a Protocol scheme used for communication on the world wide web. HTTP has many applications, but is best known for duplex communication between web browsers and web servers.
HTTP started out as a simple protocol, so you might think there wasn't much to say about it. But right now, you're holding a two-pound book. If you're wondering why we wrote a 650-page book about HTTP, check out the catalog. This book is not just a reference manual for HTTP headers; It is a veritable bible of web architecture.