This edition is a treatise on the rationale of limiting dilution analysis (LDA). LDA has evolved from its previous role as a basic research laboratory tool in virology and immunology to one pertaining to many different research disciplines and to clinical applications. New methodologies (such as PCR, confocal microscopy, in situ hybridization) have emerged, with the result that single-cell assays can now be performed on a more defined basis, and the quantitation of cells and their precursors is now more accessible to the limiting dilution approach. This book includes both detailed mathematical derivations and methodological descriptions so that the uninitiated scientist can set up and evaluate limiting dilution experiments without further instruction. It also describes particular examples of how LDA is being used to determine clinical practice.