The crisis of emerging infectious disease stems from the absence of comprehensive taxonomic inventories of the world's parasites, which includes the world's pathogens. Recent technological developments raise hopes that the global inventory of species, including potential pathogens, can be accomplished in a timely and cost-effective manner. The phylogenetics revolution initiated by systematists provides a means by which information about pathogen transmission dynamics can be placed in a predictive framework. Increasingly, that information is widely available in digital form on the internet. Systematic biology is well positioned to play a crucial role in efforts to be proactive in the arena of emerging parasitic and infectious diseases.