This document contains a summary of the lecture material. These lecture notes were created using material from Prof. Helgason’s books Differential Geometry, Lie Groups, and Symmetric Spaces and Groups and Geometric Analysis, intermixed with new content created for the class. The notes are self-contained except for some details about topological groups for which we refer to Chevalley’s Theory of Lie Groups I and Pontryagin’s Topological Groups. Documenting the material from the course, the text has a fairly large bibliography up to 1978. Since then, a huge number of books on Lie groups has appeared.