Agile Software Development – Iterative development method with a focus on efficient, user-centered product- and team management. Most agile methods like the Scrum framework are breaking down tasks into smaller sub-tasks, which are done in Sprints. Efficient face-to-face communication and fast feedback-cycles are other agile methods for maintaining quality. Compared to Lean development, the agile method focusses more on optimizing the product than the process. To learn more, have a look at this Wikipedia article about agile software development.