This publication is a user-friendly guide, taking the reader, step by step, through the trendspotter methodology developed by the EMCDDA to explore emerging drug trends, new patterns of use, developing drug markets and technologies. The trendspotter method involves the rapid collection and triangulation of data from a variety of sources, incorporating multiple social research methods, and drawing on rapid assessment and response methods. This manual is aimed at national and international agencies and organisations working in the drugs field, including research groups, community organisations, government agencies or professionals interested in applying the trendspotter methodology to rapidly identify, assess and inform about emerging drug trends.