This chapter provides an overview of metadata and how it is structured. It also describes metadata validation. Later chapters will analyze individual metadata items based on the foundation presented here. I understand your possible impatience (“When will this guy quit stalling and get to the real stuff?”) but nevertheless I urge you not to skip this chapter. Far from stalling, I’m simply approaching the subject systematically. It might look the same, but the motivation is quite different, and that’s what matters.