In this volume the philosophy of perception and observation is discussed by leading philosophers with implications in the philosophy of mind, in epistemology, and in philosophy of science. In the last years the philosophy of perception underwent substantial changes and new views appeared: the intentionality of perception has been contested by relational theories of perception (direct realism), a richer view of perceptual content has emerged, new theories of intentionality have been defended against naturalistic theories of representation (e. g. phenomenal intentionality). These theoretical changes reflect also new insights coming from psychological theories of perception. These changes have substantial consequences for the epistemic role of perception and for its role in scientific observation. In the present volume, leading philosophers of perception discuss these new views and show their implications in the philosophy of mind, in epistemology and in philosophy of science. A special focus is laid on Franz Brentano and Ludwig Wittgenstein. A reference volume for all scholars and students of the history, psychology and philosophy of perception, and cognitive science.