Concentrating on techniques for the detection and measurement of radioactivity, this book offers a guide to selecting the type of counter, type of source sample, duration for which the counting must be made, and the radiation emitted by the isotope for its efficient detection. It introduces a novel concept to explain not only the decay processes but also the selection of counting procedures for detecting and measuring radioactivity. The author builds up the foundation from the nature of the interaction of radiation with matter. He also highlights the differences between an ordinary chemical laboratory and a radiochemical one.