We study D0-brane quantum mechanics in the ’t Hooft large N limit and compare with supergravity using an analog of Maldacena duality introduced by Itzhaki &etal; To make the comparison at strong coupling, we develop a mean field approximation for quantum mechanics. We find agreement for the black hole entropy, and obtain the density of black hole microstates. By studying probe brane potentials, we reconstruct the spacetime metric from the large N quantum mechanics. ©2002 American Institute of Physics.