Non-invasive medical instrumentation is of great interest due to its use in screening and the diagnosis of patients rapidly and inexpensively. This unique, new text takes an analytic and quantitative approach to describing the basic components of the non-invasive instruments covered. The material is presented in introductory form, but it is expected that the reader has a background in basic medical physiology, cell biology, physics, engineering systems analysis, and electronic circuits for complete understanding. The relation of the parameters measured to physiological systems and health is considered in every case.