The initial impetus to create a work combining aspects of cel- lular immunology with their clinical applications grew from the ed- itors’ discussions of the area’s needs with many of the leaders in the field over a period of time. From the nucleus of ideas that emerged, we have here attempted to create a unified and inte- grated coverage of the rapidly growing field of cellular immunology research and to trace out-from what seems at times a genuine plethora of important new findings-the many and often impor- tant clinical implications. Because of this approach, the chapters of Clinical Cellular Im- munology attempt to be more than critical reviews of research and clinical data, going beyond analysis to synthesize working hypotheses about the functional meaning of cellular immunological phenomena and their likely clinical significance. To accomplish this undertaking, the text begins first with a consid- eration of the molecular aspects of antigen recognition (Luderer and Harvey) and of the ensuing regulatory program initiation (Fathman). Then, the functional subsets oflymphocytes as they in- teract to produce and control the developing immune response are explored in detail (Sigel et a1.), followed by a unique analytical dis- section of the action of immunosuppressive agents on the sundry inductive and regulatory immunologic pathways (Sigel et al.). A majority of the data and conclusions drawn by the authors in the previous chapters arise from work on murine systems, al- though wherever appropriate, human data has been introduced.