University of Pennsylvania, Philadelphia, USA

Recent developments in string and M-theory are reviewed with an emphasis on particle physics implications. Aspects of non-perturbative extended objects - branes are introduced. The focus is on the role these objects play in the construction of new four-dimensional solutions of string theory with the structure of the standard model and three families of quarks and leptons. A beautiful relationship of these constructions to purely geometric one, as an M-theory compactified on special holonomy spaces is highlighted.

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