2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190801I discuss D0-brane quantum mechanics as a nonperturbative formulation of string theory, in particular the relation between the Banks-Fischler-Shenker-Susskind matrix model, the Maldacena conjecture for D0-branes, and type IIA/M-theory duality. Some features of the quantum mechanics of D0-branes are also discussed. Lecture presented at the Nishinomiya-Yukawa Memorial Symposium, Nov. 1998.13 pages, LaTex with PTPTeX.sty, 3 epsf figures. Minor corrections and clarifications. References revisedHigh Energy Physics - Theorytext