The concept that bacteria live preferentially in matrix-enclosed communities attached to surfaces has emerged gradually from scientific observations over an extended period of time, but the pace at which this concept has advanced has accelerated sharply during the past two decades. Because Antonie van Leuwenhoek examined his own teeth scrapings with his primitive microscope, he probably saw more biofilm fragments than planktonic cells, and dental microbiologists and waste-water engineers have had a lengthy association with biofilms without using that term. Early microscopic observations of marine systems showed that most bacteria adhered actively to surfaces, and the role of surfaces in the migration and maturation of myxobacterial communities was noted very early in the study of these fascinating organisms. The new concept that was crystallized in a Scientific American article in February 1978 (Costerton, J. W., Geesey, G. G. & Cheng, K. J. (1978) How bacteria stick. Scientific American238, 86–95) was that these surface associations were the rule (and not the exception) in all nutrient-sufficient microbial ecosystems, and that most bacteria in the biosphere grow in biofilms.