At first glance, the title of this book is an obvious choice because it's the protagonist's last name. And boy oh boy, do we get an insider's look into the troubled perpetual motion machine that is Herzog's brain.
But it's not just a surface-level title. Saul Bellow is way too smart for that. When you dig a little deeper, you find that "Herzog" is actually a German word that means the same thing as "duke" in English. In other words, the last name Herzog achieves the dual effect of showing Herzog's German-Jewish heritage and suggesting that there's a long-standing pride in his family that goes back to his father's life in Europe. And this sense of pride and entitlement has certainly trickled down to our boy Moses.