we explore various aspects of black holes and gravitational theories. We focus on finding the conserved charges in gravitational theories using M method including mass, angular momentum and electric charges associated with the symmetris of the theory. We also investigate the near horizon conserved charges including supertranslation and superrotation soft charges aociated with non-trivial diffeomorphisms. Assuming Hawking mechanism for evaporation process in black holes, we introduce a maximum conjecture for the rate of entropy emission for the first time. We also address the issue about the region of origin of the Hawking quanta, using both a heuristic argument and a detailed study of the renormalized stress energy tensor (RSET). We present compelling evidence that the Hawking quanta originate from what might be called a quantum atmosphere around the black hole with energy density and fluxes of particles peaked at about 4M, running contrary to the popular belief that these originate from the ultra highenergy excitations very close to the horizon. We then study the behavior ofthe effective Hawking temperature as perceived by a free falling observer. We compute the energy density using this temperature and compare it with the energy density obtained from RSET measured by the same observer and notice a discrepancy. We further compute the adiabaticity of this temperature and try to explain the reason for this discrepancy. Finally we introduce a mathematical method for finding the exact solution for five dimensional Myers-Perry black holes using Janis-Newman algorithm.