Git is a version control system that allows tracking changes to files and coordinating work among contributors. It compares to SVN with its decentralized model where everyone has the full codebase rather than a centralized server. The key concepts covered include initializing a local Git repository, tracking file status and staging/committing changes, undoing changes, working with remote repositories on GitHub including cloning, pushing and pulling, dealing with merge conflicts, using branches to isolate work, merging branches, and advanced branching strategies like Git Flow.