Kathy Sierra has been interested in learning theory since her days as a game developer (Virgin, MGM, Amblin'). More recently, she's been a master trainer for Sun Microsystems, teaching Sun's Java instructors how to teach the latest technologies to customers, and a lead developer of several Sun certification exams. Along with her partner Bert Bates, Kathy created the Head First series. She's also 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 co-developer of Sun's upcoming EJB exam (Sun Certified Business Component Developer). His background features a long stint in artificial intelligence, with clients like the Weather Channel, A&E Network, Rockwell, and Timken. Trisha Gee is a Java Champion, published author, and leader of the Java developer advocacy team at JetBrains. She's developed Java applications for companies of all sizes in the finance, manufacturing, and nonprofit industries and beyond. Trisha has expertise in Java high-performance systems, dabbles with open source development, and is a leader of the Sevilla Java User Group.