King Size.

The story follows a young scientist in the contemporary world, who actually came from the world of dwarves, thanks to a magic potion, held by the Big Eater, ruler of the dwarves. The dwarf kingdom, Shuflandia, exists in a cellar of a library, and only the most obedient get the chance to grow to king size and inhabit the larger world. Once there, nobody wants to return to Shuflandia. Also, there are no women in Shuflandia.