Dr. Herbert Axelrod, was one of the founders of the ornamental aquarium hobby. He was the author of many books and publications, and his name is honoured in the scientific name of many aquarium fish (Cardinal tetra, Black neon tetra, Corydoras, etc.) He passed away on 15th of May 2017 at almost 90 years of age.
I'm guessing his passing will mean little to newer hobbyists. In this age of the internet there isn't the same need for printed works. For the older generation, who started dabbling in fish well before the advent of the internet, books by the likes of Axelrod were our bibles. Either way - each and every one of us, young and old, owe a debt to this man for his huge contribution to our hobby.