The physical book turned out to be surprisingly difficult to find -- no copies anywhere in the King County Library System, which was unexpected, nor in the University Library. However, I found the entire text available online, in the helpful format of each chapter being accessible through its own link on the T.o.C. Here's the link to the book as a whole:
Reading the book a few chapters per night, I found it a v. strange experience, because I kept hearing Lewis's voice, literally. I have several audiorecordings of Lewis reading aloud various essays, relics of old on-air broadcasts, and as I was reading Davidman's sentences I found Lewis's voice in my ear. Maybe it'd be different if I knew what Davidman's voice sounds like (if any recordings of her survive, I don't know about them); all I know is that Lewis intruded himself like a ghostly presence; v. odd. I don't think it was the vocabulary but, I suspect, the cadences: it'd kick in for a few sentences, then fade out, then start up again, coming in and out of focus. Which I suppose is one way of saying that Davidman successfully produced a Lewis pastiche here. Oddly enough, the introduction by Lewis was the one part that DIDN'T sound like CSL: stiff and formal and maybe a little ill-at-ease.
I have to say that, so far as the book itself goes, as a work of apologetics, I didn't get anything much out of it other than one good line. At one point Davidman offers her own, inspired, variant of Samuel Johnson's famous dictum: "Patriotism is the last refuge of the scoundrel". But in Davidman's version, this becomes
The Old Testament is the last refuge of a scoundrel
I know what she means, having grown increasingly distressed over self-proclaimed Xians who seem to take all their doctrine from the worst parts of the Old Testament. And if they do quote from the New Testament, it's almost always from Paul and not the Gospels. So the book was worth reading for that one good line -- but if I'd have known that one good line ahead of time, maybe not.
So: not as good as Lewis's better books of apologetics (THE SCREWTAPE LETTERS, THE GREAT DIVORCE, THE PROBLEM OF PAIN), but better than the worse among them (MERE XIANITY, THE ABOLITION OF MAN, MIRACLES).
just finished: THE LIFE AND ADVENTURES OF SANTA CLAUS, by L. Frank Baum (1902)
just started: THE MASK OF CIRCE, by Henry Kuttner (1948)