This book is assumed to be good for readers who are comfortable with hand-coding HTML and CSS and are familiar with the fundamentals of valid HTML5 markup and well-structured stylesheets. Basic familiarity with JavaScript is a bonus, as we will be making use of Bootstrap's jQuery plugins. We will work a great deal with LESS to customize, compose, and compile stylesheets. Those who are familiar with LESS will gain significant experience working with the details of Bootstrap's LESS files. Those who are new to LESS will find this book a reasonably thorough primer.