How smart is my dog? Smarter than I am ...

You know how something isn’t really news, but suddenly, everywhere you look, there’s a story about it? I felt like this last week, when I saw headline after headline asking me whether I know how smart is my dog.

This is all sparked by a new book called “The Genius of Dogs: How Dogs are Smarter Than You Think,” a groundbreaking work that provides evidence dogs are really, really good at reading their owners’ gestures and learning words. (When you write a book about it, it’s called a “groundbreaking work.” When you just look at your dog, wondering if he needs to go out, and he runs and gets his...