If you must know, it was some kind of nerdy nonfiction... I read about it in more than one place... it might have been a Martin Gardner column on recreational mathematics, or some other semipopular mathematical recreations book. The sort of book that has stuff like magic squares and palindromes. And gematria. I read about it in more than one place. Among other things, it showed how people always find a way to make the letters of the name of any prominent detested powerful person (e.g. Napoleon Bonaparte) add up to 666. To my mind, Heinlein's last good book was "Stranger in a Strange Land." Even then his writing was starting to get flaky at the edges. As I recall, that's the book in which his überman wise philosopher character, Jubalation T. Cornpone or whatever his name is, makes a big point of _dictating_ everything. I've always suspected that Heinlein started to use a dictating machine when he wrote that novel, and everything after that was sloppy, loosely-constructed, dictated, stream-of-consciousness, self-indulgent crap. But then Heinlein is always a writer that I have loved despite obvious flaws. That awful dialogue, half of which seems to begin with a grunt ("Uh, I guess so, Mr. Breen," "Huh? Oh, sure, if I can figure it out," "Get him here." "Eh?" "Get him down here.") The tendency for wise elder characters to pop up with maxims, well, sonny boy, don't know what fancy stuff you've been learning in school but 'pears to me that an engineer is someone who can do for two bits what anyone can do for a dollar...