I must admit that I would have liked BR/WW much more had the entire book been the epilogue. The introductory chapters and the Occupy Liberalism! chapter set the stage for a deep dive into what Mills calls "black radical liberalism" (BRL). This is an exciting project about what liberalism can be if it gets away from the (whitening) abstractions of ideal theory and accepts the central (as opposed to peripheral or deviating) reality of racist (sexist, etc) oppression. BRL accepts the truth of the radical critique of liberalism, but affirms liberalism can be transformed without destroying it. But Mills drops this and doesn't really pick it up until the brief epilogue.
The rest of the book is about the shortcomings of Kant and Rawls and all of ideal theory in understanding race and having anything useful to say about it. This is quality stuff, though I worried at points that Mills was putting a little too much effort into exegesis and not enough into showing how modern interpretations still suffer from insufficient attention to race. Especially if you've never read these sorts of critiques, they are immensely clarifying. I've read a fair bit on the shortcomings of Rawls's theory, especially with respect to gender, but nothing on Kant. The extent of his racism was a little shocking.
Back to the epilogue. Mills builds BRL out of a dialectic of three traditions: critical race theory (black), Marxism (radical), and Kantianism (liberalism). In his eventual, more in-depth exploration of BRL, I hope he branches out from these component traditions. While Marxism may offer interesting insights into class, anticapitalism will cripple BRL. The exponential productive powers of capitalism can ultimately be had without imperialism or systemic oppression, as has been argued by, e.g., Ann Cudd, a scholar Mills is sympathetic toward.
And, while the development of black radical Kantianism is a laudable project, BRL could benefit from dropping Kant and taking on a capabilities liberalism like that of Nussbaum and Sen. Capabilities liberalism already concerns itself with both the social context (in which racist and sexist oppression manifests) as well as comprehensive outcomes. Very little rebuilding from the ground up would need to be done to incorporate capabilities into BRL. Mills refers to his epilogue as also a prologue. I'm looking forward to his future development of black radical liberalism.