Proceedings of the July 1993 conference dedicated to in vivo immunology and cellular, functional, and molecular aspects of the lymphoid system. Papers feature new data and hypotheses related to non-lymphoid effector and regulatory cells, cell traffic, and the emerging field of neuroendocrine-immune interactions. Other topics include AIDS, MALT, lympho- and immunopoiesis of B and T cells, and dysregulatory aspects of the immune system.