Over the past 30 years, the study of Mycobacterium tuberculosis has become a vibrant field that supports basic investigation into mycobacteria, wide-ranging studies of M. tuberculosis pathogenesis, and drug and therapeutic development. In this minireview, we highlight the multiple ways in which M. tuberculosis is a model. M. tuberculosis has emerged as a model for prokaryotic biology, revealing basic mechanisms of gene expression, genomic integrity, and mutagenesis th