John Kloetzel studied biology at USC (A.B.) and Johns Hopkins University (Ph.D.). He then taught for 37 years in the areas of cell and molecular biology at UMBC, a University of Maryland campus. His research utilized techniques that varied from electron microscopy to gene sequencing. In retirement Dr. Kloetzel has taught OLLI courses through Southern Oregon University, in subjects ranging from basic cell biology through gene editing and the human microbiome. The microbiome course revealed that viruses deserve separate treatment; their importance extends far beyond their effects on human health. Viruses are everywhere, populating the land and sea in vast numbers, infecting all living organisms. How much, or how little, do we know about them?