Still of Marcus Whitmore (Edward Bluemel), on the set of A DISCOVERY OF WITCHES at Wolf Studios in Wales.

“AB-positive,” he said, studying me admiringly. “Wow, terrific find.” He closed his eyes and inhaled deeply. “And a witch, too!”

“Marcus Whitmore, meet Diana Bishop.”

So, even history professors make mistakes…

If you have an early edition of A DISCOVERY OF WITCHES you might read this and think, “Wait, what? My book says AB negative!” That’s right. It does.

Because I reversed universal donor and recipient in my notes, then in the manuscript, and none of us–certainly not me!–caught it. But it was corrected for the later editions.

So which version does your book have? Diana with AB-negative blood (which is a mistake), or Diana with AB-positive blood (that’s the correct answer!).