Robert E. Howard 
The Lost Race (Illustrated) [EPUB ebook] 

The novel features a muscular hero known on earth as Esau Cairn. He is transported through space to a world known as Almuric by unspecified scientific methods. While there he battles with frightening monsters and beautiful women. Cairn becomes known as the Iron Hand due to his powerful punches and boxing skills. The novel shares similar elements with the John Carter of Mars series by Edgar Rice Burroughs.