  An introduction to modern cosmology is given, focusing on theories for the
origin of structure in the Universe. After a brief review of the theory of
growth of cosmological perturbations and a summary of some important
observational results, most of the article is devoted to discussions of the
inflationary Universe scenario and of topological defect models of structure
formation. The final chapter is a summary of the theory of cosmic microwave
background temperature fluctuations and of the current observational status.
