The overarching theme of the discussion was practice, but within that framework the topics ranged from sexuality to student-teacher relationships to everyday morality to philosophy.
Disappointments first: the preface informs us that the morsels of dialogue are no longer in their original order, but were edited with an eye toward subject coherence. It might have been more interesting had the original spontaneity and choppiness of the dialogue been preserved. The book in its present state feels somewhat stilted.
Brother David also proves disappointing in two respects: first, because he has studied Zen under some of the same masters who taught Aitken-roshi, he does not approach the dialogue with a recognizably traditional Christian theology. He happily agrees with most or all of what Aitken-roshi says because he has found his own way of interpreting Christianity in a manner friendly to Zen. While this is laudable in and of itself, it makes for a dialogue between two polite fellows who agree too readily on all topics. I have never read a more conflict-free book, and I wonder to what extent such a book would benefit those Christians whose theological proclivities are more middle-of-the-road than Brother David's.
Brother David's other fault is his volubility. An Austrian by birth, Brother David has carried over into English the germanophonic tendency to speak in long, exhaustive paragraphs. The transcript is dominated by his lengthy discourses, making Aitken-roshi sound at times either meek or uninterested.
The dialogue is occasionally reminiscent of the story of the Zen master who was hosting a philosophy professor. The professor, in an attempt to impress the master, began expounding almost as soon as he entered the master's dwelling. The master, saying nothing, began pouring tea into the professor's cup. As the professor talked, the master continued pouring until the cup began to overflow. Startled, the professor cried, "Stop! No more will go in!", at which point the master said, "So it is with you. If you wish to learn something, first you must empty your cup." Brother David is obviously a learned, well-traveled individual, but I was left with the impression that his cup was full.
Despite these faults, the book is excellent as a study of how decent, civil interreligious dialogue could and should take place. It wasn't exactly a dialogue between equals (the more taciturn Aitken-roshi ends up making the deeper impression), but it produced a clutch of insights worth dwelling upon. For those looking to round out their Zen-Christian reading, I would heartily recommend this book, which also includes a fabulous list of references in the back.