John E. Clark holds a Master's Degree in Human-Computer Interaction from Georgia Tech and an undergraduate degree in Music Engineering from Georgia State University. John and his co-author, Bryan Johnson, worked together at MindSpring, and later EarthLink, starting out in technical support and documentation, before moving into application development, and finally, management of a small development team. After leaving Earthlink in 2002, John began working independently as a consultant and programmer, before starting Twelve Foot Guru, LLC, with Bryan, in 2005. John has been working with Sencha Touch since the first early beta releases. He has also worked with Sencha's ExtJS since the early days, when it was still known as YUI-Ext. When he is not buried in code, John spends his time woodworking, playing guitar, and brewing his own beer.