When Asimov was growing up, he had to spend most of his time - when he was not in scool - minding his father's candy store (in particular when his mom was pregnant with his brother Stanley.)
Asimov could have ended up doing many things - sitting around staring vacantly into space, playing with computer games (if only they'd been invented back then), watching TV (if only it had perfected - it had been invented) etc., but in fact "This forced me more firmly into the world of books, and I became an assiduous librarygoer."
He states in his autobiography:
"I read omnivorously and without guidance. I would stumble on books about Greek myths and fell in love with that world. When I discovered William Cullen Bryant's translations of the Illiad and the Odyssey I took them out of the library over and over."
He read Dumas and Dickens and Louisa May Alcott, "and indeed, almost the entire gamut of nineteenth century fiction." Because so much of it was by British authors, "I became a spiritual Englishman and a conscious Anglophile."