In this book, Bryan Wesley Hall breaks new ground in Kant scholarship, exploring the gap in Kant's Critical philosophy in relation to his post-Critical work by turning to Kant's final, unpublished work, the so-called Opus Postumum. This volume provides a powerful alternative to all current interpretations of the Opus Postumum, arguing that Kant's transition project is best seen as the post-Critical culmination of his Critical philosophy. Hall carefully examines the deep connections between the Opus Postumum and the view Kant develops in the Critique of Pure Reason, to suggest that properly understanding the post-Critical Kant will significantly revise our view of Kant's Critical period.

"Hall's study offers a very clear, rigorous, stimulating and original attempt to reconstruct the systematic continuity between Kant's critical and post-critical philosophy, rightly emphasizing the central meaning of the a priori concept of the ether in OP [Opus Postumum]." - Giovanni Pietro Basile, Hochschule für Philosophie München