Abstract: Recent observations provide a firm ground for inflation as a theory of early
universe and structure formation. However, the origin of inflation is not well-understood theoretically. Brane inflation is a realization of inflation from string theory. In its simplest form, the inflationary potential is derived from the attractive force between a brane and an anti-brnae. Furthermore, in these models, cosmic strings are copiously produced.  Observing these cosmic strings can provide a unique window on superstring theory in the sky. In this talk some aspects of of brane inflation are reviewed and implications of cosmic strings for lensing, CMB anisotropies and gravitational wave emission are studied.