Kathy Sierra has been a software developer (games and AI) and a master trainer for Sun Microsystems, coaching Java instructors on how to teach the latest technologies to customers. She is a lead developer for most of the Sun certification exams. She is the original founder of the Software Development/Jolt Productivity Award-winning javaranch.com, the largest (and friendliest) all-volunteer Java community.
Bert Bates is a 20-year software developer, a Java instructor, and a lead developer of most of Sun's Java certifications.
His background features a long stint in artificial intelligence, with clients such as the Weather Channel, A&E Network, Rockwell, and Timken. Together with Kathy Sierra, Bert created the Head First series.