HTML

HTML is the language that describes the structure and the semantic content of a web document. Content within a web page is tagged with HTML elements and these elements form the building blocks of a website.
Site: https://developer.mozilla.org/en/docs/Web/HTML

Books

Added HTML and CSS is hard

A friendly web development tutorial for complete beginners.

 Free book

Added Learn to Code HTML & CSS

Learn to Code HTML & CSS is an interactive beginner’s guide with one express goal: teach you how to develop and style websites with HTML and CSS. Outlining the fundamentals, this book covers all of the common elements of front-end design and development.

 Free book

Added HTML5 for Web Designers

HTML5 isn’t as confusing as it once was, but it still isn’t straightforward. It’s an evolutionary, rather than revolutionary, change in the ongoing story of markup—and if you’re currently creating websites with any version of HTML, you’re already using HTML5.

 Free book