Scrum is an agile development methodology that focuses on roles, backlogs, and time-boxed meetings. There are three core roles: the Scrum Master enforces practices and removes roadblocks, the Product Owner maintains the backlog and user stories, and the self-organizing Team delivers working software each sprint. Artifacts include the Product Backlog of prioritized user stories and the Sprint Backlog of selected stories. Sprints are 30-day cycles where selected stories are demonstrated as shippable at the end. Meetings include Planning, Daily Scrums, a Sprint Review, and Retrospective.