Several decades ago Mark Kac asked his famous question:"Can one hear the shape of the drum?" - in other words- under which conditions, if at all, can the frequency spectrum of the drum vibrations determine the shape of the drum's boundary.This problem has many important implications in physics and mathematics, and in the first part of the talk I shall review the present status of this subject. In the second part, I shall address the new version of the question, in which one replaces "hear" by "count".