Fifty years of caring. Kaiser Permanente turns 50 this year.

It's been said that major, landscape-changing events can sometimes stem from the humblest of origins: The gentle flutter of a butterfly's wings, the theory states, can begin a sequence of events that profoundly alters the weather pattern of an entire continent. In the world of science, this phenomenon is known as "chaos theory." But in the dynamic environment of the U.S. health care system--where the HMO philosophy has profoundly alter the way health care is delivered and financed--it has another name: Kaiser Permanente. From the humble yet revolutionary idea of a young surgeon caring for Depression-era workers in the Mojave Desert, to the current 6.7-million-member organization that has served as a model for plan administrators and policy makers across the country, Kaiser Permanente has originated, endured, and contributed more to the health care marketplace over the past 50 years than probably any other entity. Now, on Kaiser Permanente's golden anniversary, as the health plan reflects on its accomplishments and influence, it is plotting a course for quite challenging times ahead.