David J. Perdue (http: //www.davidjperdue.com/) has been inventing robots with MINDSTORMS since 2001. The author of Competitive MINDSTORMS: A Complete Guide to Robotic Sumo Using LEGO MINDSTORMS (Apress, 2004), he has also written for BrickJournal and Computing Unplugged. Perdue is an implementation delivery engineer for EMC, an information infrastructure provider. He lives in St. Paul, Minnesota.
Laurens Valk is a member of the MINDSTORMS Community Partners, and one of his robots appears on the NXT 2.0 box. Valk is the author of The LEGO MINDSTORMS NXT 2.0 Discovery Book, a co-author of LEGO MINDSTORMS NXT One-Kit Wonders (both No Starch Press), and a contributor to The NXT Step Blog. He lives in the Netherlands where he studies Mechanical Engineering at Delft University of Technology.