Sharon Kay Penman has some very famous friends.

The first was Richard III, the 15th century English king immortalized by Shakespeare as a hunchbacked, womanizing, nephew-imprisoning power monger. Penman stumbled onto a revisionist history of his life in the 1960s, and was both fascinated and sucked in by its polar opposition to the narrative she thought she knew — promptly beginning an ad hoc, one-woman mission to resurrect his good name.

“I was pushing my friends against walls at parties and telling them how history had mistreated him,” she recalled, a little ruefully, by phone from her home in New Jersey.”And I got the same reaction from all of them: ‘Richard who?’ Then when I started to explain, their eyes would glaze over and they’d sidle away. So I decided that if I wanted to save my social life, I would have to find another outlet for that.”

Lucky for us, she did. She told Richard’s story in “The Sunne in Splendor” (St. Martin’s Press) in 1982, after 12 years of working on it in every moment she could snatch from getting and practicing her law degree. “I didn’t like the law at all,” confessed Penman. “I considered it penance.”

So she turned her prodigious attention entirely to writing, deciding to hang around in the Middle Ages. “I was just always fascinated by the time period. It's very dramatic, and of course as a writer I could do fun things like besiege castles. I really never thought about moving to another [one].” Her next project was a trilogy set in 13th-century Wales, charting the collision course between Celtic society and the English kings’ feudal realm.

Then the Angevins moved in. Her 15 years of writing about King Henry II and his family have included a trilogy of historical fiction and four mystery novels centered around Henry’s widow, Eleanor of Aquitaine. The third book in the trilogy, “Devil’s Brood” (Ballantine Books), is making its paperback appearance this summer, and Penman is celebrating with a short American book tour that stops at Nicola’s Books on Wednesday, Aug. 5.

If you are new to Penman’s writing, you’re in for a delicious treat. Her account of the last days of this powerful king’s reign is fast-moving, sharp-tongued and richly detailed, taking you with her everywhere she goes. She introduces us to each of his passel of children — legitimate and otherwise — and manages to tell both sides of his bitter split with Eleanor in a sympathetic manner that looks a lot like the vast gray chasm of the family rifts we’re familiar with, in which there are almost never the clear winners that history so likes to assign.

Penman said she thinks that in this cast of characters, “there really weren’t any villains. There were just some very flawed human beings. In Henry's case, he was a brilliant man and a great king, but such a bad father. And yet he loved his sons desperately and was never able to understand why they kept rebelling against him. He strikes me as one of Shakespeare’s great characters, brought down by his own flaws. Eleanor did learn from her own mistakes, although of course she had 16 years of ‘leisure’ [when she was imprisoned by Henry for her part in a rebellion] to think about them.”

Getting to know the formidable Eleanor of Aquitaine, duchess in her own right, wife of two kings and mother of three more, was a particular joy. “She was a law unto herself,” said Penman. “You can’t judge other medieval women by her, because she broke every law in the book and still casts the same spell eight centuries later.” Even so, the queen found herself constrained figuratively and literally by the explicit legal power of the men around her, and one adviser is forced to tell her plainly that she is “crippled by her skirts.” But Penman doesn’t take the easy view on that, either: “The position of women in the Middle Ages was very complex, not as simple as is sometimes felt. The common law was then a woman and a man were one — and the husband was the one. But certainly women of the middle class took part in the family business. … And women of the upper class were expected to run a royal household; if the husband was away, the wife was expected to rally the knights in defense of it. [When I wrote] ‘Here Be Dragons,’ which is the story of King John's illegitimate daughter who married a Welsh prince, I was fascinated that women in Wales enjoyed so much more freedom than their sisters across the channel. So it's dangerous to generalize.”

For Penman, history isn’t just good book fodder or a quirky personal interest, it’s a tool for grounding one’s whole existence. “It disturbs me enormously when people seem so indifferent to the lessons of the past,” going on to note as an example how infrequently current analysis of the tumult in Iran takes into account the long history of hostilities between that country and ours. “And as far as seeing things from a wider perspective, that's important, too. We don't feel quite so alone in the world when we know that we're following in the paths of others. I find that very comforting.”

Sharon Kay Penman will be at Nicola's Books, 2513 Jackson Ave., at 7 p.m. on Wednesday, Aug. 5 to read and sign “Devil’s Brood.”

Leah DuMouchel is a free-lance writer who covers books for AnnArbor.com.