Fifty years of illumination about the natural levels of adaptation Jacobus J. Boomsma  Current Biology  Volume 26, Issue 24, Pages R1250-R1255 (December 2016) DOI: 10.1016/j.cub.2016.11.034 Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 1 The three innovators who shaped the modern general theory of adaptation. Niko Tinbergen (1907–1988), George C. Williams (1926–2010), and William D. Hamilton (1936–2000), who published their seminal contributions in the 1960s. Pictures, from 1964, 1962 and 1967, respectively, are courtesy of the families of Niko Tinbergen, George C. Williams, and William D. Hamilton, the latter © British Library Board. Current Biology 2016 26, R1250-R1255DOI: (10.1016/j.cub.2016.11.034) Copyright © 2016 Elsevier Ltd Terms and Conditions