Allison here has written one of the most important pieces of Kant scholarship in the last century. In my view, this book should serve as the starting point for any new inquiry or research into Kantian philosophy. It exposes the severe weaknesses of what Allison refers to as the 'standard picture of Kant', or in other words, the mainstream perception and narratives surrounding Kant's philosophy. He seeks to address to the main misinterpretations and objections to transcendental idealism, with a focus on modern commentators. This is done with admirable depth, textual support and clarity. Although Allison is not alone in voicing these rebuttals, with other writers such as Beiser also pointing out such lazy misconceptions, this book remains useful for its compactness and explicit goal of addressing such problems.
The book is split into several sections, including a general sketch of modern Kant scholarship and Kantian philosophy, with particular focus, unsurprisingly, on the Critique of Pure Reason. There are a total of 15 chapters in four sections. These sections are 'the nature of transcendental idealism', 'human knowledge and its conditions', categories, schemata, and experience', and 'the phenomenal, noumenal, and the self'.
Of particular value here is Allison's discussion of Kant's distinction between transcendental idealism and transcendental realism, and the further distinction between transcendental and empirical versions of ideality and reality. These distinctions often ignored by Kant commentators, and much of their criticism results from a misunderstanding of these distinctions. An example I'll touch on is the work of H.A Prichard.
Prichard's influential critique of Kant involves an attack on Kant's view of appearances, stating that since Kant believes we only know appearances, he is forced, in virtue of his doctrine of the ideality of space and time, either to say that space is an illusion, or the appearances themselves are spatial. Since Kant wants to safeguard empirical realism, he is forced to say that appearances themselves are spatial, which is absurd. However, this is a complete neglect of the different standpoints Kant takes when discussing appearances - the transcendental and empirical. Prichard's claim is only true if we take Kant to be talking about appearances in the empirical sense, but if we see it from the transcendental perspective, as Kant wanted us to, then this claim is false. Taken transcendentally, spatiality is considered as a defining characteristic of how things appear, not as a property attributed to sensation itself.
Another interesting point about Allison's interpretation of Kant is that he takes transcendental idealism not to be a simple metaphysical or epistemological philosophy, but also what he calls a meta-philosophical or meta-methodological viewpoint. The critique, it can be claimed, is dealing with the question of whether we can isolate a set of conditions of the possibility of knowledge of things from the possibility of the existence of those things themselves. The standard picture of Kant does not even address this question, and so, is forced to take a psychologistic reading of the Kantian project, which entails untenable conclusions.
Other valuable discussions that take place involve an in depth analysis of the thing in itself, and the associated criticisms of the affection theory.
This is a very rewarding read for anyone interested in Kantian philosophy and in my opinion presents the most complete and accurate exposition of transcendental idealism. A much more coherent account than the typical strawman's of Kant that are presented and accepted in the 'common knowledge' of the philosophical community.