Abstract
In this chapter P-decay is discussed as a tool for studying the structure of atomic nuclei. An attempt is made to give a simple account of the topic so that the student can understand what they find in the literature about beta-decay. The quantities of spectroscopic interest are defined and the student is shown how they can be derived from experiments. In the study of exotic nuclei often the first thing we learn about a nucleus is how it beta-decays. A series of examples of beta-decay studies of exotic nuclei is presented with the aim of both illustrating the most up-to-date techniques and showing the student the breadth of physics that can be addressed