There's an old publishing quip about the difference between guy books and girl books: men like to read about a lot of characters dying very quickly, while women like to read about a single character dying very, very slowly.

The joke hints at a serious issue. Estimates are that up to 70% of fiction buyers, and 80% of fiction readers, are female.

My novels always have strong and smart female characters, but they usually also have a male protagonist. They have battles (lots of people dying very quickly), intricate plots, and no character-developing "disease of the week."

In other words, statistically I'm doomed.

My latest novel, Blood of the Reich, does have a female as its primary hero and three other important female characters to balance the four primary males. But it also has a Nazi Iron Cross on its blood red and steel gray cover, and a complete absence of hearts, flowers, children, pets, or ripped bodices.

The marketing reasoning behind the cover is that I can't afford to alienate my core readers, men, and women are more open. Women will pick up a thriller cover with an Iron Cross—a 2000 survey showed they make up 69% of thriller buyers—but men will never, ever, pick up, say, a chick lit–looking cover.

So how can I persuade female buyers (in the reported 17 seconds they consider buying any book in their hands) that alongside my suspense on Nazis, particle physics, and lost city shootouts is romance, longing, and the courageous character arc of an appealing young woman?

The question is: what do women readers want? I've asked this of book clubs I've visited (always exclusively female) and their answer is not long deathbed scenes from tragic illnesses (though I'm guessing that wouldn't hurt) but relationships. Romance. Food. Cool places to hang out, like castles and palaces. And sex, if tastefully calibrated.

Women like action, but they want stuff happening inside to people as well as outside to armies. Scientists report that women are hard-wired for empathy, probably because it was an evolutionary advantage in raising children and a disadvantage in spearing enemies.

Twenty-first–century ladies are also stern. No wimp women, they warn. No shrieking ninnies. They want authors who understand them.

What guy can do that?

My wife has prohibited me from having female characters who pout or giggle.

"But women do pout or giggle, at least once in a while," I tried.

"Not in your books they don't," she said.

Adding mystery to the gender conundrum is that the majority of enduring literary and movie series characters have been male: for every Miss Marple there is a testosteroned platoon of Sherlock Holmes, James Bond, Horatio Hornblower, Indiana Jones, or even Updike's Rabbit Angstrom and Roth's Nathan Zuckerman.

Women buy the fiction. But they will read about men.

My plan for world domination, then, is to appeal to both sexes. It would be fascinating to publish Blood of the Reich with two titles and two covers, crassly calculated to cover the men are from Mars, women are from Venus dichotomy.

Failing that, I merely hope that women really are less close-minded than men, and will give an Iron Cross book a try, will identify with heroic innocent Rominy Pickett, and will tell their friends. Just in case, I've also got a tomboy, Buddhist nun, and Nazi, to cover all the bases.

Here's the secret: in the end, I don't think men and women are so different after all. The books that move me don't just blow things up, they feature males and females seeking connection and purpose. That's what people do. So it's not just smart to have good female characters. It's a necessity.

William Dietrich is a Pulitzer Prize–winning journalist and New York Times bestselling author; his latest novel, Blood of the Reich (Harper), came out last week.