Since the 1780s, Western philosophy has been largely under the spell of Immanuel Kant's transcendental philosophy. In this book, Maurizio Ferraris offers a number of important criticisms of Kant in a book of two parts, written 21 years apart. The first part of the book, 'Observation', originally published in 2001, lays the foundations of Ferraris' New Realism, foreshadowing the realist turn that has become characteristic of 21st century philosophy. The second part, 'Speculation', written in 2021, outlines a complete metaphysical theory of realism. What ties both parts of the book together is the the notion of hysteresis, the ability of effects to survive even when their causes have ceased to exist.