This second edition has been completely revised and updated. The text has been expanded to include a section on validation of integrators in response to regulatory requirements for quality and validation. A literature survey, additional diagrams and Author Index have also been added. The book describes and discusses both manual and electronic techniques used, with the aim of aiding analysts to obtain more data from their chromatograms, and assist them with understanding how integrators work so that results are not accepted unquestioningly.