Globally renowned HIV researcher Opendra “Bill” Narayan, of the University of Kansas Medical Center, died unexpectedly at the age of 71. Bill, a veterinarian and virologist, obtained fame over a decade ago after creating a type of HIV that resulted in a disease in monkeys that resembled AIDS in humans. His outstanding accomplishments and contributions in the field were a testimony to the Pioneer Award in neurovirology that he received in 2006. Reflections from his past trainees about his mentoring and teaching skills and their interactions with him are a small tribute to this larger than life legend. Opendra “Bill” Narayan, an internationally recognized scientist and pioneer in AIDS research, died on December 24, 2007 at the age of 71. For those people in so many fields who knew him, his death has left a large void. Born in Essequibo, Guyana in November 1936, Bill developed a fascination for natural sciences from an early age, and this attraction led him to pursue a career in science. He received his doctorate in veterinary medicine at the University of Toronto, Canada in 1963 and his doctorate in the mechanisms of viral disease at the University of Guelph in 1970. Bill’s interest in animal viruses took him in 1972 to the laboratory of Dr. Richard T. Johnson, a preeminent neurovirologist, in the Department of Neurology at Johns Hopkins University Medical Institutions (JHUMI). It was in 1973 that he initiated and pioneered studies on infection in sheep with slow-moving viruses, called lentiviruses. When it was discovered 15 years later that HIV belonged to the lentivirus family, Bill’s research took on a whole new direction. “When HIV was isolated and it was discovered that it was also a lentivirus, Bill was in an ideal position to play a leadership role,” wrote Diane E. Griffin, Professor and Alfred and Jill Sommer Chair of the Department of Molecular Microbiology and Immunology at Johns Hopkins Bloomberg School of Public Health in Baltimore. It is his pioneering work on visna and subsequently for the development of animal model of AIDSand HIV-associated dementia with which his name will forever be linked. Bill’s dedication and passion for science raised him through the ranks at JHMI to Professor and Director of the Retrovirus Biology Laboratory. His deep sense of social responsibility and his concern about making a worthwhile contribution to benefit mankind were reflected in his choice of research topics in a career spanning almost four decades. J Neuroimmune Pharmacol (2008) 3:1–4 DOI 10.1007/s11481-008-9101-y