est em (えすとえむ, Esu to emu,, S and M) is the pen name of Maki Satoh, a Japanese manga artist who debuted with three yaoi collections after being scouted in art school. She was a student of Matt Thorn, who provided translations for some of the English licenses of her work. Her work has been praised as having unusual maturity and depth, both for yaoi and for manga in general.