It seems like every semi-competent pregnancy book is really the thin wedge of some doctor's publishing empire. I don't know yet about the spin-offs and follow-ons, but these three baby book brands have done alright by us so far. My advice: slow down and buy such books one at a time, as needed.
They're all written "to" women, but the first one, at least, is fine for guys involved with a pregnancy (The other two are useful for amusing a pregnant woman in an informative way, but they're annoying as hell for a guy to read.)
1) the encyclopedic What to Expect When You're Expecting.
2) the chick-centric infotainment of A Girlfriend's Guide to Pregnancy (which apparently includes detailed discussions of the hangups and quirks of record industry executive Jimmy Iovine, since it's written by his chatty wife) and which produced bouts of laughter, followed immediately by bouts of tears.
3) A Bun in the Oven is very funny, reassuring (because no woman will gain as much weight as the author did), but not overly informative.
You may want to leave the room and start picking up around the house if either of these last two books comes off the shelf. While I got The Expectant Father as a gift, I didn't find it much more use than What to Expect. The bullet points for dads: do more housework, and, well that's mainly it.