Are there Jewish sources which affirm the validity of the art of palm-reading? If yes, how does this work. i.e. what is the underlying idea behind it.

(the reason I ask, is because I actually met someone in Jerusalem with a thick book of haskomos (approbations) from reliable Rabbis about his palmreading skills. Even Rabbi Yaakov Hillel, in private, said of him that he has a "mesorah" (tradition) on the art.)