Dr Michael J. Manyak is Vice President for Medical Affairs for Cytogen Corporation. He is also a professor of Urology, Engineering Microbiology, and Tropical Medicine at The George Washington University and on staff at the Center for Prostate Disease Research at Walter Reed Army Medical Center. Dr. Manyak is a medical advisor to several field exploration organizations, was selected as a Fellow National of The Explorers Club in 1992, and received their Sweeney Medal in 2004. His column on Expedition Medicine currently appears in Explorer's Journal.