This article reviews the methods of measurement which allow us to infer the presence of magnetic fields in (A) stars. Beginning with the basic observational consequences of the Zeeman effect, we describe various modern spectroscopic and polarimetric techniques which allow us to directly detect and characterise magnetic fields in stellar photospheres. Sometimes, nature conspires to make such detections difficult, forcing us to rely on indirect (proxy) indicators of magnetism. This talk will also briefly discuss a number of these indirect field indicators, some of which demand space-based observations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html