Paul Horowitz is Professor of Physics at Harvard University, where he teaches physics and electronics. He originated Harvard's Laboratory Electronics course, now in its 20th year, and is the co-author of The Art of Electronics. His research interests include observational astrophysics, x-ray and particle microscopy, optical interferometry, and the search for extraterrestrial intelligence. He is the author of some 150 scientific articles and reports, has consulted widely for industry and government, and is the designer of numerous electronic and photographic instruments.