the early centers were very focused on demography, and they were fractionated with few common projects across centers. The idea behind the RSI was to provide basic lectures in each of several areas both to attract new scholars into research on aging and to form a more integrated research program. The first forum was held in Chicago in the afternoon prior to the start of the Annual Meeting of the Population Association. On the plane to Chicago one of us (RS) noticed that Dr. Robert Wallace, a physician epidemiologist, was his way to the University of Iowa, and cornered him and persuaded him to delay his trip and give an impromptu presentation on epidemiology of aging -one of the best that afternoon.The Centers have become much more integrated than at first. They work together on many projects, sharing costs and contributing ideas. They now form the essential infrastructure for the social sciences related to aging. The RSI has undergone a similar Population Ageing (2015) 8:1-5 Media Dordrecht (outside the USA) 2015 broadening, as several subfields of psychology have been integrated into the RSI, and a separate but contiguous "Mini-Medical School for Social Scientists" has been added to provide a taste of biology, clinical medicine and genetics.Participants in the RSI are selected competitively and need not be affiliated with one of the centers, and faculty are invited from research centers around the world, but inevitably the Centers are heavily represented at all levels every year. The topics discussed at the Institute dovetail nicely with the year-round work of the centers. Through funding of pilot projects, the centers have helped young scholars get established in productive careers or lured talented senior researchers into aging. Lists of seminars and visiting fellowships, or of publications produced by center affiliates, would show the same progress that the master lectures at the summer institute review. The centers have celebrated milestone anniversaries at the summer institute, and the tradition has grown of marking anniversaries with special issues of leading journals: James Vaupel gave a 1994 Master Lecture on mortality of the oldest-old, beginning a Summer Institute tradition of luring young scholars into aging by presenting paradoxical findings challenging orthodoxy (in this case, the universality of the smooth Gompertz curve.) Burton Singer took on in 1994 what was even then a vast topic, the relationship between socioeconomic status and health. It had been known since pioneering studies of the 1970s that social connections profoundly influence health at older ages. In this special issue, the article by Wong and Waite (2015) takes advantage of a data source, the National Social Life, Health and Aging Project, which provides much greater detail about the social environment than was available two decades ago. They show that aspects of the quality of relationships matter more than the quantities ("connectedness") assessed in earlier studies, and that the quality of marriage and intimate partnerships affec...