When Fred Griffith was carrying out his pioneering work on the epidemiology and pathology of bacterial pneumonia in the 1930’s medical mycology was almost invisible in comparison to the well-established fields of medical bacteriology, virology and parasitology. However, fungal infections now account collectively for more annual deaths than malaria or tuberculosis and they represent a significant worldwide challenge and health burden. The sharp rise in the prevalence of life threatening fungal infections tracks the emergence of large numbers of AIDS infections and other immune compromised individuals, who are often particularly vulnerable to life-threatening fungal infections. Recent efforts have begun to address these clinical needs, and have established medical mycology and fungal immunology as fertile areas of basic and applied research that have contributed broadly to our appreciation of host-microbe interactions and microbial pathogenesis. Using some vignettes from recent research highlights and contributions from my own group’s work, this lecture will attempt to demonstrate how efforts to understand and undermine fungal disease processes are underlining the credentials of medically important fungi such as Candida, Aspergillus and Cryptococcus species as pathogens to rival the best known bacterial, viral and parasitic pathogens of the modern world.