And even I can remember A day when historians left blanks in their writings, I mean for things they didn''t know. -Ezra Pound, Canto XIII * The prefaces to the previous volumes of this series have all expressed in various ways the actual motivation behind these collective efforts. There was agreement in most instances that we are facing some kind of publication explosion, and that the present type of compact and personalized reviews may be of help, from both a conceptual and a purely informational standpoint. The aims of the series were, and still are, to focus attention on the rapidly changing fields within the realm of immunology, and to present in each chapter the summation of results generated by an investigator or group of Investigators, either as an analysis of their own work or as a correlation of such work with the general field in question. The present volume does not differ in its construction from its predecessors, although it does concentrate on a single target, the T lymphocyte and its biology. The selection of subjects as well as contributors has been the sole responsi bility of this editor; however, the actual format and length of the individual contributions was left to the discretion and inspiration of the different authors. Even the styles, ranging from the concise statement to the meticulously detailed review, attest to the freedom of format.
