Agile development is an iterative approach to software development that values individuals and interactions, working software, customer collaboration, and responding to change over following a strict plan. It utilizes short development cycles called sprints that are typically 2-4 weeks to deliver working, tested software increments. Key roles in Scrum, a common Agile framework, include the self-organizing development team, Scrum Master who facilitates the process, and Product Owner who represents customers and priorities features. The team works from a backlog of features, breaks them into tasks, tracks progress on a board, and demos working software daily to integrate customer feedback into future sprints.