Just to add some context to my review, I am a graduate student in architecture doing an independent study on Kahn's work. That doesn't mean you should listen to me, but simply that I care about this.
There is a clear attempt by Bell and others to cash in on Kahn's popularity by adding texts to the end which are close to useless vis-a-vis an attempt to comprehend the lecture. Kahn's use of so many idiosyncratic phrases compells anyone compiling his work to explain, as best he or she can, what those mean. This is sadly lacking. If I knew what "white light, black shadow" meant to Kahn, I'd be better prepared to engage the text. One could claim Barthe's intentional fallacy, but, I think that's a bad excuse.
Additionally, the introduction doesn't give an adequate summary of the political/social climate surrounding the talks, ie. Vietnam, King's death, etc., which I think plays a part in understanding the phrase "white light, black shadow" as well as others.
That said, the lectures are really stunning, and, suprizingly accesible after a few reads. An overall continuity is harder to come by, but within a page or so range, there is a strong logic to his thinking. I don't know if this lecture is reproduced anywhere else, if you can't find "white light, black shadow", it would be worth the purchase. The question and answer is also interesting, but less so. Again, Bell should go hug someone, he clearly needs it.