There’s nothing unique about a wisecracking private investigator. Smart-mouthed PIs are a dime a dozen. Every private eye writer in the last thirty years has one—and for good reason. They’ve all read the Spenser novels, and they’ve molded their private eyes after him. I know I did. When I started my first Stanley Hastings novel, back in the mid-80s, I wanted a private eye that talked like Spenser. Never mind that my private eye was an ordinary family man who never had fist fights or car chases, and didn’t even carry a gun. (I was working as a PI at the time, chasing ambulances for a negligence lawyer, and I modeled the character after myself.) If my PI could talk like Spenser, I was convinced he’d be fun to read.

Other writers felt the same. And so a whole generation of clever PIs was born. Many were closer to Spenser than mine, being tough and athletic and jogging and having dangerous sidekicks like Hawk. But all, to the best of their authors’ abilities, talked like Spenser.

And yet Spenser stands out.

It is not just that he is better at it, though he is. His remarks are rooted in his personality. Spenser is a knight in shining armor, a do-gooder, a man who lives by a code of honor, with values and standards and principles. His jests humanize him, mask his heroism, diffuse the macho image that is rightfully his. Without humor, he would appear a self-righteous prig, adhering to a strict moral  …