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.

Bryan P. Johnson is a graduate of the University of Georgia. Bryan went to work for MindSpring Enterprises in late 1995, where he met his co-author John Clark. At MindSpring, and later Earthlink, for over seven years, Bryan served in multiple positions, including Director of System Administration and Director of Internal Application Development. After leaving Earthlink, Bryan took some time off to travel before joining John in starting Twelve Foot Guru.

Bryan has worked with Sencha's products since the early days of YUI-Ext and has used Sencha Touch since its first betas.