Despite being a curable and preventable disease, tuberculosis is the leading cause of death from infection worldwide and is one of the top 10 causes of death from any cause, including in children. Incidence is at best barely declining, increasing in some countries, and some prevalence surveys in high-burden countries have demonstrated a significantly higher tuberculosis burden than estimated. Between a quarter and a third of the world's population is estimated to be infected with tuberculosis, representing a vast reservoir from which new cases arise. Many of these people are never identified or tested, and even among those who are, only a small proportion receive preventive treatment. Interventions that aim to increase preventive treatment uptake and completion are likely to have a greater impact on tuberculosis control and elimination than those focussing on improving completion of treatment by patients...