Theodore Gray is the author of How Things Work, The Elements, Molecules, and Reactions, as well as Theodore Gray’s Completely Mad Science. He is the creator of the bestselling iPad apps “Elements” and “Molecules,” which have both been named App of the Week by Apple, and he was the director of “Disney Animated” (also honored by Apple as iPad App of the Year). Gray appeared onstage with Steve Jobs several times in his capacity as a software creator. He also co-founded Wolfram Research, Inc., makers of the widely used software Mathematica and the Wolfram Alpha website. He lives in Urbana, Illinois.

Nick Mann is a photographer specializing in taking beautiful photos of inanimate objects on black backgrounds. His other work includes The Elements, Molecules, Reactions, and How Things Work. In his other life he designs and makes specialized note- taking fieldwork equipment, as well as working in the quality control department for a large automotive company. He lives with his wife and stepson in Urbana, Illinois.