From Wikipedia's article on Robert Heinlein's Space Cadet <https://en.wikipedia.org/wiki/Space_Cadet https://en.wikipedia.org/wiki/Space_Cadet> (1948): >The no

From Wikipedia's article on Robert Heinlein's Space Cadet <https://en.wikipedia.org/wiki/Space_Cadet https://en.wikipedia.org/wiki/Space_Cadet> (1948): >The novel contains an early description of a mobile phone: >>Matt dug a candy bar out of his pouch, split it and gave half to Jarman, who accepted it gratefully. "You're a pal, Matt, I've been living on my own fat ever since breakfast -- and that's risky. Say, your telephone is sounding. "Oh!" Matt fumbled in his pouch and got out his phone. "Hello?" >The phone "was limited by its short range to the neighborhood of an earth-side [i.e. terrestrial] relay office". I especially find this part insightful: >A cadet avoids having to talk to his family while traveling by packing his phone in luggage.