I'm shocked this book isn't better known, and popular amongst Kant circles. It took me hours of book research just to find out it exist. This is a shame, because Hartnack's introduction to Kant's theory of knowledge is the best I've ever read. He breaks the entire Critique of Pure Reason into 142 pages, and does so without missing any primary points. The book is a chronological summary of every chapter, and subsection, of Kant's masterpiece. And Hartnack does not leave the reader disappointed. One could argue that the downside to his presentation is that Hartnack never considers present debate about what Kant said, but that's really missing the point of the book. He wants the reader to know what Kant said, but whether or not Kant was right is up to the readers’ discretion, and future research. If anyone wants to read the Critique of Pure Reason for the first time, or even a second, or third, this is an ideal companion. It also serves as a great reference book, since every chapter is summarized. If you forget what Kant's position on cosmology was, merely open this book, and in 5-7 pages, you'll have your memory refreshed.