Agile and Lean software development methodologies for iterative, adaptive project execution. Covers Scrum (roles, ceremonies, artifacts), Kanban (WIP limits, flow metrics), XP (TDD, pair programming, CI), SAFe overview, Lean Software Development (Poppendieck's 7 principles), user stories (INVEST criteria), estimation via story points and velocity, and the Agile Manifesto's values and principles. Includes Cynefin framework for methodology selection and GSD's relationship to Agile as a structured Lean variant.