From the Preface: Jack Kiefer’s sudden and unexpected death in August, 1981, stunned his family, friends, and colleagues. Memorial services in Cincinnati, Ohio, Berkeley, California, and Ithaca, New York, shortly after his death, brought forth tributes from so many who shared in his life. But it was only with the passing of time that those who were close to him or to his work were able to begin assessing Jack’s impact as a person and intellect. About one year after his death, an expression of what Jack meant to all of us took place at the 1982 annual meeting of the Institute of Mathematical Statistics and the American Statistical Association. Jack had been intimately involved in the affairs of the IMS as a Fellow since 1957, as a member of the Council, as President in 1970, as Wald lecturer in 1962, and as a frequent author in its journals. It was doubly fitting that the site of this meeting was Cincinnati, the place of his birth and residence of his mother, other family, and friends. Three lectures were presented there at a Memorial Session - by Jerry Sacks dealing with Jack’s personal life, by Larry Brown dealing with Jack’s contributions in statistics and probability, and by Henry Wynn dealing with Jack’s contributions to the design of experiments. These three papers, together with Jack’s bibliography, were published in the Annals of Statistics and are included as an introduction to these volumes.