Optogenetics came onto the scene with the same lightning bolt as its opsins. Decades of research on rhodopsins and photostimulation of neurons culminated in the ground-breaking and wondrous year of 2005, including the first report of behavioural control of an animal via genetically targeted photostimulation (Susana Lima and Gero Miesenböck; Cell, 121 (1): 141–52) and the first single-component optogenetic system for neural control, using channelrhodopsin-2 (ChR2; Ed Boyden and Karl Deisseroth, including Georg Nagel who developed the ChR2–eYFP construct; Nature Neuroscience, 8 (9): 1263–8). In Optogenetics: From Neuronal Function to Mapping and Disease Biology (2017), Krishnarao Appasani edits an encyclopaedic volume on the ins and outs of optogenetics. Nagel pens the foreword and reminds us that rhodopsins, ChR2 included, were not ‘invented for optogenetics’, and that their discovery ‘resulted from basic research on light-sensitive membrane proteins and on phototaxis on green algae’. As with many other scientific fields, optogenetics owes an immense debt of gratitude to transdisciplinary basic research. More than 10 years on, Appasani’s collection does a good job of reviewing the state of the art of the field, from the biology of opsins and their use in different model organisms to the applications of optogenetics in neuropsychiatric, memory and vision research. Technical details aside, one essential message of this volume is clear – that optogenetics will keep on shining for many years to come.