When President Nixon wanted to overhaul the health care system to provide universal coverage, his administration turned to Stuart Altman. Ten years later, when Congress created a commission to improve the Medicare payment system, Altman led the effort. And, in the early '90s, when newly elected Bill Clinton assembled a team to guide his health care policies, Altman was among the first chosen. There may be no single person with a longer or deeper history in the health care overhaul efforts of the past 40 years than Altman, a professor of national health policy at Brandeis University in Waltham.