Alex Libby has a background in IT support. He has been involved in supporting end users for almost 20 years in a variety of different environments; a recent change in role now sees Alex working as an MVT test developer for a global distributor based in the UK. Although Alex gets to play with different technologies in his day job, his first true love has always been with the open source movement, and in particular experimenting with CSS/CSS3, jQuery, and HTML5. To date, Alex has written 11 books on subjects such as jQuery, HTML5 Video, SASS, and CSS for Packt, and has reviewed several more. Responsive Web Design with HTML5 and CSS3 Essentials is Alex's twelfth book for Packt, and second completed as a collaboration project. Dan Wellman is an author and frontend engineer living on the South Coast of the UK and working in London. By day he works for Skype and has a blast writing application-grade JavaScript. By night he writes books and tutorials focused mainly on frontend web development. He is also a staff writer for the Tuts+ arm of the Envato network, and occasionally writes for .Net magazine. He's the proud father of four amazing children, and the grateful husband of a wonderful wife.