CHARLES S. SELL, PHD, has recently retired from Givaudan after thirty-six years in the fragrance industry. His work has covered all aspects of synthetic organic chemistry as applied to the fragrance industry, from discovery of novel materials through process R&D to improvement of established chemical manufacturing processes. His interest in the design of novel fragrance ingredients, coupled with a long-standing interest in the chemistry of living organisms, led to a deepened investigation into olfaction.