On April 11, 2019, the American Academy of Arts and Sciences presented the Rumford Prize to six scientists for the invention and refinement of optogenetics. The awardees are Ernst Bamberg, Professor and Director of the Department of Biophysical Chemistry at Max-Planck Institute of Biophysics; Edward Boyden, Y. Eva Tan Professor of Neurotechnology, Associate Professor of Biological Engineering and Brain and Cognitive Sciences at MIT’s Media Lab and McGovern Institute for Brain Research, and Co-Director of the MIT Center for Neurobiological Engineering; Peter Hegemann, Professor and Head of the Department for Biophysics at Humboldt University of Berlin; Gero Miesenböck, Waynflete Professor of Physiology and Director of the Center for Neural Circuits and Behavior at the University of Oxford; Georg Nagel, Professor at the University of Wuerzburg (Bavaria); and Karl Deisseroth, D. H. Chen Professor of Bioengineering and of Psychiatry and Behavioral Sciences at Stanford University. Lucia Rothman-Denes, A. J. Carlson Professor of Molecular Genetics and Cell Biology at the University of Chicago, introduced the prize recipients and presented the award. Edward Boyden accepted the award on behalf of all the prize recipients. An edited version of his acceptance remarks appears below.