The death of Bernie O'Brien in February 2004 brought a premature end to one of the most productive and influential careers in the area of health technology assessment and economic evaluation. A long-term member of the Society for Medical Decision Making, Bernie will be remembered for his research contributions in areas including outcome valuation, decision modeling, statistical methods in economic evaluation, and applied cost-effectiveness studies. He was also an excellent communicator and teacher and, above all, a fun guy to work with. In this article, the authors provide a review of Bernie's academic contributions.