Some thirty years ago it was discovered that black holes radiate and that they have an entropy proportional to their surface area. Using string theory methods, one can evaluate the entropy of black holes by dual descriptions of space-time. One can also inquire about the entropy of enanglement of the vacuum state of the black hole which arises from an observers inaccesibility to the region beyond the horizon. In this talk, we will review this type of entropy and relate it to the black hole entropy evaluated by string theory.