The continuous advances in our understanding of hematology and neo plastic disorders have made possible this third volume of reviews. Their purpose is to summarize investigations which have defined new concepts, and, it is hoped, stimulate new ideas. In the choice of subjects, we have attempted to retain the balance between academic and clinical interests. We are grateful to the contributors, who have maintained the high stan dards set in the earlier volumes, and for feedback from readers. Both have helped to orient the direction of this series. It was a reader who pointed out that the title of the two earlier volumes, The Year in Hematol ogy, was misleading since it suggested a detailed review of trends and findings limited to the last year. In response to this valid comment, The Year . . . has been changed to Contemporary . . . and the scope has been expanded to encompass the kindred disciplines of hematology and oncol ogy. Another editor, Franco M. Muggia, has been added to provide addi tional expertise for the latter field. The title of the present and future volumes has been changed to Contemporary Hematology/Oncology. It has been pointed out to us that considerable ingenuity will be needed to find topics not already covered. We believe that the papers in the present volume have met this challenge. As before, the readers' comments con cerning Contemporary Hematology/Oncology will be appreciated. Joseph LoBue Albert S. Gordon Robert Silber Franco M.