In 1965, Mary J. Marples ’ seminal book The Ecology of ’ Human Skin was

Clinical Infection. Skin microbiology as a subject with its own intrinsic interest and also one that contributes to other disciplines may, therefore, be said to be fast approaching maturity. I t is interesting to examine the changes that have occurred in this time, but it is essential to understand that, in the early years, appreciation of the intrinsic interest of skin microbiology was limited; skin was simply another surface that needed disinfection before surgery. It is convenient to discuss the evolution of the subject in three principal parts: (i) a more precise definition of the skin microflora, (ii) interactions between members of that flora (coactions), and (iii) interaction between the flora and the host. Finally, some lacunae in our present knowledge will be explored. The resident skin flora Before the work of Marples (1965) i t was thought possible to dismiss the normal skin flora as comprising micrococci and diphtheroids with a few yeasts. Now we expect a normal healthy adult to carry several representatives of the genera Stapliylococcus, Micrococcus, Propionibactcrium, Corynebacterium, Brevibacteriun