Children’s authors Peter Barnes and Cheryl Shaw Barnes for years have used cute, friendly mice as a way to explain the intricacies of the U.S. government to children.

In “House Mouse, Senate Mouse,” the husband-and-wife team introduce Congress to kids using the “Squeaker of the House” and the “Senate Mousejority Leader.” In “Woodrow for President,” another mouse runs to be the “Commander in Cheese.” Then there’s “Marshall, the Courthouse Mouse,” who teaches youngsters about the “Supreme Court of the United Mice of America.”

But the authors were feeling a bit squirrelly when they created the protagonist of their latest book, “Cappy Tail’s Capitol Tales.” Meet Cappy, a friendly gray squirrel who takes readers on an educational (and surprisingly detailed) tour of the Capitol complex.

The idea for the book and its cuddly hero came from Capitol officials, who asked the Barneses to create a children’s book about the recently opened Capitol Visitor Center. The couple happily signed on — although Cheryl Barnes admitted she wasn’t so sure about that whole squirrel-as-the-main-character idea.

“I’m like, ‘A squirrel? They’re rats with big tails,'” she said. Her view changed after she spent some time sitting on the squirrel-filled Capitol grounds.

“I saw some awfully cute squirrels,” she said, laughing. “Now I like squirrels.”

In the colorful book, Cappy takes readers on a tour of the Capitol, explaining the landmark’s history from President George Washington laying the first cornerstone to the opening of the CVC. But putting the story together wasn’t as simple as having Cappy take kids around and spout a few facts (as some unscrupulous interns have been known to do while giving tours).

Cheryl Barnes spent about two years meeting with Capitol Hill experts — from the curator for the Architect of the Capitol and the Secretary of the Senate to Capitol guides and the CVC gift shop manager — to ensure readers experienced an informative, true-to-life tour.

Not only did she work hard to get the facts correct, Barnes spent much of her time making sure her illustrations would be spot-on. And because there are places in the Capitol she couldn’t photograph, she relied on images from books and the Internet to replicate certain spaces.

Her inspiration? Constantino Brumidi, nicknamed the “Michelangelo of the Capitol” because he spent 25 years painting most of the fresco paintings in the building.

“I figured if Constantino Brumidi could [create] those incredible murals and incredible work in the Rotunda for 25 years or almost 25 years of his life, I’m going to try to do the artwork as accurate as possible,” Barnes said.

Cappy begins his tour at the CVC, where in a rhyming prose he shows off Emancipation Hall, the Statue of Freedom and the view of the Dome. The squirrel then escorts his tour group to the Rotunda, where he points out Brumidi’s “The Apotheosis of Washington” on the ceiling.

As Cappy explains, “The Rotunda is magnificent, as anyone can see/The paintings tell the story of our early history/High above he sits, commanding over this great hall/ The Father of our Country, proudly watching over us all.”

Barnes admits she “didn’t even know what a apotheosis was” when she began the book. “I learn as I go,” she joked.

Other stops on Cappy’s Capitol tour: Statuary Hall, the Old Supreme Court Chamber, the Crypt, and the House and Senate chambers. “I learned the rug in the Senate has about 100 bazillion dots in it because I drew every one of them,” Barnes said.

Rather fittingly, Cappy ends the tour by pointing out a Brumidi painting of a squirrel, located near the Patent Corridor in the Senate wing of the Capitol.

“Cappy Tail’s Capitol Tales” is available in the gift shops across the Capitol complex.