Git is an open source distributed version control system designed for speed and efficiency. It was initially developed by Linus Torvalds for managing the Linux kernel source code. Key concepts in Git include repositories for storing project data and history, revisions (commits) for capturing snapshots of file changes, branches for isolating work, and distributed collaboration through cloning repositories. The document provides exercises for configuring Git, creating and working with repositories, commits, branches and merging, and collaborating via cloning, fetching and pushing changes.