William (Bill) S. Hammack (born 1961) is an American chemical engineer, and professor in the department of chemical engineering at the University of Illinois at Urbana–Champaign.

[1] Hammack is well known for his ventures in science communication as the persona Engineer Guy: between 1999 and 2005 he produced radio commentaries for Illinois Public Media, and starting in 2010, he produced a regular series of videos on YouTube explaining the engineering of everyday objects.

[2][3] He also authored the book The Things We Make: The Unknown History of Invention from Cathedrals to Soda Cans.

[4] Hammack received his Ph.D in Chemical engineering in 1988 from University of Illinois, Urbana-Champaign under the guidance of Harry Drickamer.

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