This chapter seeks to provide clinicians with a better understanding of prisons and overcome many of the myths and misconceptions, with the objective of making the environment more attractive and interesting for future psychiatrists. In addition to a wide need and a rich variety of conditions, the psychiatrist in prison must contend with barriers to care such as working without a mental health act and, when a patient needs to be transferred and treated outside of prison, navigating complicated pathways to care. Mental disorder is prevalent in all prison systems. Pathways into prison may be related to general factors, specific factors such as delusions and comorbidities and complications of mental illness such as homelessness and breakdown of relationships, as well as service provision issues. The prevailing policy has been to divert prisoners in need of hospital care out of prisons. Court diversion models can focus on any point in the pathway from community to the criminal justice system. In prison, specialist mental health services are needed to address the high levels of morbidity due to self-harm, drug use, suicide and self-harm, hunger strikes and many other manifestations of developmental problems and traumatic experiences.