There are many definitions of Agile Method Project Management, but the official one is provided by the Project Management Body of Knowledge (PMBOK). PMBOK is basically a guidebook for those who work in project management, and the official definition of Agile Method Project Management can be found in section 8.2.1. In short, it states that Agile Method is a specific approach to project management that uses iterative strategy, adaptive planning, and incremental development.