Proceedings of the Waltham Symposium on Taurine and Cat Nutrition, held October 1991, and of the International Taurine Symposium: New Dimensions on its Mechanisms of Action, held October 1991, in Orange Beach, Alabama. The single biggest factor in elucidating the many functions of taurine in the last 20 years has been the special importance of this compound for the cat, and the recognition of the importance of this animal in taurine research. The interests of pet food producers and veterinarians have ramifications for research involving the heart, development, the central nervous system, the lung, and osmoregulation.