Differentiation of instruction is often misconstrued. It would be handy to represent differentiation as simply instructional decision making through which a teacher creates varied learning options to address students’ diverse readiness levels, interests, and learning preferences. Although that approach is attractive because it simplifies teacher thinking, administrator feedback, and professional development design, it is ineffective and potentially dangerous. To see differentiation as an isolated element reduces teaching to a series of disconnected components that function effectively apart from the whole. The more difficult and elegant truth is that effective teaching is a system composed of interdependent elements. As with all systems, each part is enhanced when others are enhanced, and each part is diminished when any part is weakened.