“This comprehensive primer on the internal operations of WebKit and Gecko is the result of much research done by Israeli developer Tali Garsiel…Web browsers are probably the most widely used software. In this primer, I will explain how they work behind the scenes. We will see what happens when you type google.com in the address bar until you see the Google page on the browser screen.”

This is a great article that gives a comprehensive view of what actually happens in the back-end of your web browser engine. The article seems to focus primarily on the WebKit and Gecko engines and how they retrieve and render Google’s homepage.

How Browsers Work: Behind the scenes of modern web browsers (html5rocks.com)