Daniel BaumannLiam McAllister2024-02-262024-02-262009-01-030163-89981545-4134https://scholars.lib.ntu.edu.tw/handle/123456789/63994860 pages, 1 figure. Invited review to appear in Annu. Rev. Nuc. Part. SciWe provide a pedagogical overview of inflation in string theory. Our theme is the sensitivity of inflation to Planck-scale physics, which we argue provides both the primary motivation and the central theoretical challenge for the subject. We illustrate these issues through two case studies of inflationary scenarios in string theory: warped D-brane inflation and axion monodromy inflation. Finally, we indicate how future observations can test scenarios of inflation in string theory.CMB polarization | Gauge/gravity duality | Inflationary cosmology | String inflation; High Energy Physics - Theory; High Energy Physics - Theory; astro-ph.CO; General Relativity and Quantum Cosmology; High Energy Physics - Phenomenologyjournal article10.1146/annurev.nucl.010909.0835242-s2.0-75449120143http://arxiv.org/abs/0901.0265v1