This special issue presents findings from a collaborative project funded by the ESRC's Global Challenges Research Fund, which researched prisons in Guyana. The project was a partnership between academics from the universities of Guyana and Leicester and officers in the Guyana Prison Service. The disciplinary backgrounds of the university researchers spanned history, criminology, public health, anthropology, sociology, and politics and international relations, while officers were drawn from all ranks including welfare and medical staff. Clare Anderson and Mellissa Ifill's previous work, funded by the British Academy and supported by researchers Estherine Adams and Kellie Moss, uncovered the history of colonial-era practices and operations in Guyana's prisons, up to Independence in 1966 Moss et al., 2020). Prison officers immediately saw contemporary resonances and proposed that we might explore the post-colonial impacts of approaches to incarceration in the country now.In the ESRC project, we grew our team and co-developed work that centred on colonial history, the post-Independence period and the present day. Our objective was to construct what we called a 'usable past' that would bring attention to the ongoing aftermaths of colonial-era prison discipline and could thus nurture reform. While we were interested generally in law, infrastructure, penal discipline, rehabilitation and resistance, our attention was drawn especially to the use and experiences of drugs, including alcohol, among prisoners and the people who work with them, and how we might trace historic continuities in contemporary approaches to, and desires and framings around, substance use. This connected to mental ill health, which was one of the key challenges that the Prison Service had signalled to us as we developed our relationship through our historical work, and which is relevant to both prisoners and staff (Anderson, Moss & Adams, This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.