I bought a number of books about being pregnant and found them all overwhelming, too serious and completely dull!
My husband bought "Fatherhood: The Truth" for himself and chuckled his way through the whole thing, often laughing out loud and then looking sheepish. He said it was brilliant and, once he read it, he was certainly more understanding of what I was going through.
I then decided I had to read it and also chuckled throughout. I laughed out loud at the idea of 'Competitive Dad' syndrome as the first thing my husband bought for our baby was the fanciest baby monitor he could find!
Finally, a book that allows you to laugh rather than cry at all the changes that are happening and about to happen!
(I should mention that it is definitely aimed at potential fathers so some potential mothers may not find it so amusing - if you can't take a joke, don't read it. But you should still buy it for your husband!!)