The sensitivity principle is a compelling idea in epistemology and is typically characterized as a necessary condition for knowledge. This collection of thirteen new essays constitutes a state-of-the-art discussion of this important principle. Some of the essays build on and strengthen sensitivity-based accounts of knowledge and offer novel defences of those accounts. Others present original objections to sensitivity-based accounts (objections that must be taken seriously even by those who defend enhanced versions of sensitivity) and offer comprehensive analysis and discussion of...