For the bee-curious dad (who may or may not be a beekeeper):
He's likely to enjoy Thomas D. Seeley's 2010 book Honeybee Democracy (Princeton University Press) and recently featured on NPR. Seeley is a professor of biology at Cornell and a passionate lover of and advocate for honeybees. In this latest book, he describes how honeybees make collective decisions about where to locate a new colony when they swarm. From this, Seeley draws some delightful conclusions about how humans can make better collective decisions. The writing is lively and fascinating. The book is available on-line for about $20.
For the dad who loves honey and wants to know more about it:
Check out Kim Flottum's The Backyard Beekeeper's Honey Handbook. I reviewed this book in Review of Honey Cookbooks, Part I. It's written for beekeepers, but provides a very nice discussion of honey varieties, talks about how to treat honey well and includes some great recipes, too. You might also look for Gene Opton's Honey: A Connoisseur's Guide, (reviewed in Review of Honey Cookbooks, Part II), though it's out of print, and may take some searching to find.
For the beekeeping dad who like gadgets:
One of the handiest gadgets we've added to the many beekeeping gadgets we've purchased over the years is a simple and compact cigar lighter that makes lighting a smoker a dream. If your dad's a beek and doesn't have one, he'll thank you for it! You might also look for a "frame holder" or "frame perch" which is a handy when you're beekeeping on your own. They're available at all major beekeeping supply places. (Joe Z. at Country Barn Farm is a local distributor for Brushy Mountain. Blue Sky Bee Supply in Hiram, Ohio is another small and fairly close source.)