New religious movements are often described as bizarre and sinister. Direct acquaintance, however, often gives a different impression from media portrayals and even from some academic writing. After decades of undertaking fieldwork, the author George Chryssides discusses his experiences, as well as studies by other scholars, and the issues that fieldwork involves. How do one's personal beliefs and lifestyle impinge on field research? How involved should a participant–observer become? How should we assess what we are told by insiders and ex-members? What ethical problems does field research create? How should we engage in online fieldwork, arising from the increasing use of the Internet, accelerated by the Covid pandemic? These are among the issues which this Element explores, and which will be of interest both to field researchers and to those who read about the fieldwork of others.