This is really just a sequence of rough capsule biographies of scientists who were interested in light.
It has a bunch of illustrations of the different biographical subjects.

It starts too early, with the ancient Greeks (Democritus) through Roger Bacon. The second chapter covers Galileo and Descartes. Galileo actually tried to measure the speed of light, so he definitely merits a mention. Roemer and Cassini both tried to measure the speed of light using the perceived variation in the eclipses of the moons of Jupiter when Jupiter was closest and furthest from the earth. As with many of the incidents mentioned in this book, I would have had no idea of the basic idea without having read "The Sun and its Family" by Irving Adler. Newton and Huygens get a mention, but they do not seem to have done much with the speed of light. James Bradley used the aberration of starlight to calculate the speed of light (in "The Sun and its Family" there is a description of how the aberration of starlight was used to calculate the velocity of the earth, and hence the AU.). Foucault and Fizeau did some earthbound experiments to measure the speed of light through various media. James Clerk Maxwell's equations; he believed in the aether. Michelson's experiments seemed to show that the speed of light was a constant. Max Planck originated quantum theory. Albert Einstein had his big year. A Danish physicist called Lene Hau put light through some remarkable medium that made it travel so slowly that a cheetah could have beaten it.

Charles Wheatstone is called "a French scientist" in this book, Wikipedia disagrees and I think it's correct.

Overall, this book doesn't give anything like its title promises. ( )