Scrum is a popular agile framework that helps development teams deliver value in small increments, typically 30 days or less, through short sprints. It provides a flexible framework for self-organizing teams to focus on delivering working software frequently. Key roles in Scrum include the product owner who prioritizes backlog items, the Scrum master who facilitates the process, and cross-functional teams of 7 plus or minus 2 members who are responsible for delivering working increments of software.