Most people are familiar with the principles that underly traditional phased-based, sequential development. However, the principles that underly agile development are different and frequently not understood, even by practitioners of agile. It is common when people first learn agile to focus on the mechanics of a specific agile approach such as Scrum or Kanban. Knowing the mechanics (the “what” and the “how”) is necessary, but not sufficient for successfully applying agile. Without an understanding of the core principles, the “why” is missing. These principles provide the foundation for understanding and applying agile approaches. Implementing something like Scrum — even by the book— without understanding these principles is one of the leading causes of organizational failure with agile. People who apply Scrum without understanding its underlying principles lack the necessary context to understand why they are doing things and when and how best to inspect and adapt their approaches. Whether you are a developer, manager, or executive you need to understand core agile principles if you want to successfully apply agile. In this presentation, I provide an overview of core agile principles with an emphasis on how they are different than the core principles that underlie traditional development.