Charles Gerba, Ph.D., is an internationally renowned environmental microbiologist who made his reputation a quarter of a century ago by opening scientists' eyes to the dangerous things lurking in our groundwater. His lab created the first test to detect the parasite cryptosporidium in water, changing the way municipalities treat tap water. He is a professor at the University of Arizona where he oversees cutting-edge experiments in the department of Soil, Water & Environmental Science. He has performed thousands of studies on everything from water quality in our homes to urine levels in community pools, from the germs present in airline bathrooms to pathogens in home hot tubs. His quick wit has endeared him to American audiences as Dr. Germ, and he appears regularly on Good Morning America, Dateline, CNN News and 60 Minutes as well as national magazines and newspapers. He lives with his wife in Tuscon, Arizona.