Mark Bell is a middle school science and technology teacher residing in Los Angeles. His passion for designing things, debugging them, and requirements engineering has led to a twenty-five year career as a technologist in support of aerospace, military, education, and the intelligence community. For the last decade, Mark has been an instructor with gifted, young robotics students in the Johns Hopkins Center for Talented Youth. He teaches regularly at several locations in the US and Hong Kong. James Floyd Kelly is a professional writer from Atlanta, Georgia. He has written numerous books on multiple subjects, including LEGO robotics, open source software, and building your own CNC machine as well as a 3D printer.