Welcome to the Harm Reduction Digest, where in each regular edition of Thug and Alcohol Review invited co‐authors will contribute to pieces on the theory and practice of harm reduction. While the focus of subsequent HR Digests will be accounts of the practice of harm reduction interventions, programmes and policies from around the world, it was decided that the first Digest ought to address the definition of Harm Reduction. Consequently the style of this digest is probably more formal than most that will follow it. Many of you will have read DAR's special issue on harm reduction (1995, 14(3)) where Alex Wodak, Bill Saunders, Patricia Erickson, Eric Single and Nick Heather all addressed the issue of definition in their respective contributions. Since this there have been a handful of papers and reports which have also grappled with the issue of definition. Co‐author of this piece is Professor Eric Single, from the Department of Public Health Sciences at the University of Toronto. Eric addressed issues around the definition of harm reduction in the 1996 Dorothy Black lecture in London and, with Professor Timothy Rohl, as independent evaluators of Australia's National Drug Strategy, wrote on the topic in their report ‘Mapping the Future’.