The manual is written for clinicians working at the district hospital (first-level referral care) who diagnose and manage sick adolescents and adults in resource constrained settings. It aims to support clinical reasoning, and to provide an effective clinical approach and protocols for the management of common and serious or potentially life-threatening conditions at district hospitals. The target audience thus includes doctors, clinical officers, health officers, and senior nurse practitioners. It has been designed to be applicable in both high and low HIV prevalence settings. Volume 2 provides a symptom-based approach to clinical care for acute and subacute conditions (including mental health). It provides short summaries of the management of diseases that affect multiple systems of the body, focusing on communicable diseases. It also includes the chronic or long-term management of HIV, TB, alcohol, and substance use disorders.