Gladiator

Gladiator is a science fiction novel by Philip Wylie. The classic inspiration for Superman!

Gladiator tells the story about a scientist who invents an "alkaline free-radical" serum to "improve" humankind by granting the proportionate strength of an ant and the leaping ability of the grasshopper. 

The scientist injects his pregnant wife with the serum and his son Hugo Danner is born with superhuman strength, speed, and bulletproof skin. Hugo spends much of the novel hiding his powers, rarely getting a chance to openly use them.

The novel is widely assumed to have been an inspiration for Superman due to similarities between Danner and the earliest versions of Superman who debuted in 1938.

Gladiator was first published in 1930. Audiobook read by Mike Pelton, running time 7 hours, 46 min. Unabridged full version. Also available as E-Book: ePUB, 75,100 words, average reading time 6 hours, 15 min. 

Philip Gordon Wylie (1902–1971) was an American author of works ranging from pulp science fiction, mysteries, social diatribes and satire, to ecology and the threat of nuclear holocaust.