The analysis generated a range of specific findings and confirmed some prior expectations based on research in other countries, including the facts that drug dealing cycles are short (often a week or less) and that price as a function of transaction size is well described by a power function. The findings document empirical regularities that call for theoretical analysis and explanation, such as the apparent stability in price markup coefficients over drugs and time. Also generated were new insights such as evidence that the United Kingdom importers might be vertically integrated into high-level domestic distribution. Much of their net revenues is derived from the domestic distribution, not solely from importation, and can be attributed to compensation for enforcement risk. Revenue does behave as risks and prices theory would predict, with bigger risk compensation increments for heroin and cocaine, than for cannabis. Data were collected from 222 incarcerated drug dealers in 22 cooperating prisons. Tables and figures