This document discusses an introduction to browser internals presented at Barcamp Bangalore 2014. It covers how browsers work behind the scenes including parsing HTML, constructing the DOM tree, applying CSS styles, executing JavaScript, laying out pages, and more. The rise of Chrome and fall of Internet Explorer market share is shown. Hands-on demonstrations are provided of manipulating the DOM in real-time to see how browsers operate. Resources for learning more about browser engines like WebKit and building your own browser are also listed.