[Yadi]

I would recommend you to look into this book: HTTP: The Definitive Guide

As a web developer understanding how the Internet stack and some specific protocols work, could very easily make your life easier.

[aprdm]

This does indeed look like a great book but it's from 2002, I understand that the internet changed a lot in the last 13 years?

[Yadi]

This is about the fundamentals of HTTP, most of the changes are based on these fundamentals.