Of all Barry H. Landau's anecdotes about his friendships with presidential dogs - and trust us, he has lots of 'em - perhaps the best is the one about the time the Clinton White House called to postpone his play date with Buddy.

Yes, Landau is both human and an adult - a 60-year-old author, presidential historian, former White House protocol officer and memorabilia collector. But so enamored is he of dogs, and so well connected to a succession of presidents, that he had an appointment for a South Lawn romp one day with Buddy, Bill Clinton's Labrador retriever.

Logistics got in the way, though, and hence Clinton secretary Betty Currie's apologetic voice mail left at the Smithsonian Institution, where Landau was doing research: "I'm sorry, but we'll have to reschedule Mr. Landau's play date with Buddy."