Over the past centuries physiology has weathered a series of revolutions generated by the introduction of powerful tools and concepts from other disciplines, notably physics and chemistry. On each occasion such infusion of new ideas has enormously strengthened and enriched physiology. Today, the introduction of tools and concepts from engineering promises another revolution with another strengthening and enrichment. Among the things engineering has to offer are some that are close to the heart of physiology. These must be adapted and thoroughly integrated into the body of physiological concepts, attitudes, and operations. This goal presents a challenge which physiologists cannot afford to ignore. It calls for an "operation bootstrap" on the part of those of us long past our student days. It will entail a changing pattern of undergraduate preparation and graduate education for those who will become the physiologists of the coming generation. But a welcoming of the challenge and an encouragement of efforts to meet it will transform this opportunity, as others have been transformed, into another revolutionary advance in physiology.