Martin Maiden is Professor of Molecular Epidemiology at the University of Oxford. His work has provided fundamental insights into the epidemiology, population biology, and evolution of bacterial pathogens. His ground-breaking contributions include the development of multi-locus sequence typing which has been applied to most bacteria of medical and veterinary importance. MLST has enabled detailed investigation of outbreaks, defined routes of dissemination and acquisition, informed vaccine design/implementation, and provided insights into microbial virulence. He has been at the forefront of efforts to derive the genome sequences of an entire year’s isolates of N. meningitidis from England and Wales - a landmark project which provides the first nationwide genome-level surveillance of a major pathogen.