Dog on the Roof!

They were the typical American family on a typical American road trip—Dad behind the wheel, Mom in the passenger seat, their five adorable kids piled in the back. And, of course, their beloved dog strapped to the roof.

Wait . . . what?

Now for the first time, here is the completely true—and only mildly embellished— shaggy-dog story of Seamus Romney, the famously fetching Irish setter whose master,...