Dr. Stephen P. Maran spent more than 35 years in NASA, working on the Hubble Space Telescope and other scientific projects, and is the press officer for the American Astronomical Society. His 10 previous books include 'Astronomy for Dummies' ® and 'The Astronomy and Astrophysics Encyclopedia'. His awards and honors include the naming of an asteroid for him by the International Astronomical Union, the NASA Medal for Exceptional Achievement, the American Astronomical Society's George Van Biesbroeck Prize, and the Astronomical Society of the Pacific's Klumpke-Roberts Award for outstanding contributions to the public understanding and appreciation of astronomy. Residence: Chevy Chase, MD. Laurence A. Marschall, PhD, is the WKT Sahm Professor of Physics at Gettysburg College where he teaches courses in astronomy, physics, and science writing.

He received his bachelor's degree at Cornell University and his doctorate at University of Chicago. He writes a regular column on science books of note for 'Natural History' magazine, is a contributing editor of 'Smithsonian Air and Space', and contributes annual astronomy updates to 'The World Book Encyclopedia'. He serves as deputy press officer of the American Astronomical Society. In addition to more than 40 articles in professional journals, Marschall has written for publications such as 'Sky and Telescope, Astronomy, Natural History, Discover, Harper's, Newsday,' and 'The New York Times Book Review'. Residence: Gettysburg, PA.