no fewer than a half million patients: Bowersox 1999.

the evolution of the peppered moth: The British geneticist Bernard Kettlewell (1907–79) conducted much research on the peppered moth and industrial melanism. His findings have been questioned by some (eg, Wells 2000; Hooper 2003), and supported by others (eg, Majerus 1998). A popular-science summary of the debate is de Roode 2007.

the famous philosopher of science: Popper 1976, p. 151.

did recognize his error: Popper 1978; also Miller 1985.

termed by modern evolutionary biologists genetic drift: There exists vast literature on genetic drift. An online lecture by Stephen Stearns can be found at www.cosmolearning.com/video-lectures/neutral-evolution-genetic-drift-66 87. Other easy-to-access online resources include Kliman et al. 2008, and www.ucl.ac.uk/~ucbhdjm/courses/b242/InbrDrift/InbrDrift.html. A comprehensive textbook on population genetics is Hartl and Clark 2006.