The present volume of Current Topics in Microbiology and Immunology c- tains seven chapters that illuminate various aspects of a protein's genesis and terminal fate in the endoplasmic reticulum (ER). This area is of immediate medical relevance and has blossomed, to no small extent, because of the study of molecules central to the function of the immune system immunogl- ulins, T cell receptors, major histocompatibility complex (MHC)-encoded products]. Similarly, the clever strategies used by bacteria or viruses to gain a foothold in the host and ensure their continued survival have uncovered...