This thesis has its roots in and has organically grown out of the author’s previous professional civil service roles and academic and related activities associated with drug indicators since 1987. However, the focus of the present work is on providing a description and critical evaluation of developments in the epidemiology of drug-related mortality in the United Kingdom (UK) over the past three decades or so, and how an understanding of that knowledge has been disseminated and impacted policy and practice. First recognised as a major issue by the Advisory Council on the Misuse of Drugs in its seminal 2000 report, a lot of effort and resources have gone into tackling drug-related mortality. Despite this, the number of deaths rose steeply across the UK up until very recently; however, until the effects of the Covid-19 pandemic on death registrations are known and understood, the apparent levelling off may be an artefact of reporting. The increased numbers of deaths occurred against a background of improvements in case identification, investigation, and reporting - with associated public health and law enforcement initiatives. As far as the author can establish, there has been no overview or in-depth study of drug-related deaths (DRDs) in the UK and associated issues. Furthermore, there has been no detailed description of the processes underlying how such events have been identified, investigated, recorded, analysed and the information about them disseminated. Moreover, no study of a comprehensive nature has been conducted into what has been occurring, what insights are now available that were non-existent three decades ago, and what uses have been made of that knowledge. The aim of the programme of research reported here was to rectify the lack of knowledge in these areas and to start to fill the deficits and provide a framework for future research.