Training to become a chemistry teacher entails acquiring sufficient knowledge of chemistry (chemistry content knowledge) as well as the knowledge, skills and abilities with which to package, repackage, and present chemistry concepts (contents) in a form which is consumable (fathomable and understandable) by target students. This chapter considers the important features of chemistry as a body of knowledge, features which inform and shape how chemistry teachers (including trainees) should think about chemistry as a school subject, plan and implement chemistry teaching.