With 2 million deaths per year, TB remains the most significant bacterial killer. The long duration of chemotherapy and the large pool of latently infected people represent challenges in disease control. To develop drugs that effectively eradicate latent infection and shorten treatment duration, the pathophysiology of the causative agent Mycobacterium tuberculosis needs to be understood. The discovery that the tubercle bacillus can develop a drug-tolerant dormant form and the identification of the underlying genetic program 10 years ago paved the way for a deeper understanding of the life of the parasite inside human lesions and for new approaches to antimycobacterial drug discovery. Here, we summarize what we have learnt since the discovery of the master regulator of dormancy, DosR, and the key gaps in our knowledge that remain. Furthermore, we discuss a possible wider clinical relevance of DosR for 'nontuberculous mycobacteria'.