The main fieldwork of the study was conducted in Her Majesty's Prison Wellingborough between October 2002 and August 2003, following a 2-month pilot study in spring 2002. The author's first 3 months of fieldwork were spent observing daily practices and interactions in the prison and talking informally with staff and inmates about prison life. Informed by this initial phase, the months that followed consisted of a large number of long, semistructured interviews with 70 inmates. The importance of drugs in daily prison life was apparent from the early stages of the pilot study. Drug-taking and dealing were accepted by officers and inmates as inevitable features of the inmates' world. Heroin was brought into the prison in a number of ways, the most common being through corrupt staff, friends, and family during visits or in letters. Once inside the prison, drugs are stored and sold through complex networks of trade and friendship. Heroin's value in prison is three to four times its street value. Inmates ingest their drugs in small groups in their cells, while nonusers tend to avoid public areas when drugs are in heavy use. In manipulating others and feigning friendship, heroin users undermine general levels of trust and other traditional features of the inmate code regarding interactions with other inmates. Overall, the heroin-based inmate culture accentuates inequalities between the powerful and the vulnerable and increases the amount of power that can be exercised in prison. Social relations are destabilized by inmate interactions that are exploitive, manipulative, and based on self-interest. 9 notes and 54 references