The impact on mathematics of the paper ''Oscillation and Chaos in Physiological Control Systems'' by Mackey and Glass in Science, 1977

The note describes the role of the Mackey-Glass equation and of a similar equation due to Lasota in the study of nonlinear delay differential equations between 1977 and 2012, as far as rigorous mathematical results are concerned, and from the very personal point of view of the author’s involvement.