Books in the Barrier Breaker series celebrate the achievements of individuals during various periods of American History. The Cook Who Defended Pearl Harbor features Dorie Miller, who joined the Navy, shot down two enemy planes, and became the first Black American to receive the Navy Cross. Hitting Her Way to the Negro Leagues introduces Toni Stone, who earned her nickname, Tomboy, while playing baseball on a boys' team. She became the first woman to play on a Negro League baseball team. In 1993, she was honored by inclusion in the National Baseball Hall of Fame. Mailing Himself to Freedom describes the ordeal of Henry Box Brown, an enslaved man. In 1849, he crouched in a wooden box, which his friends took to a transport company for delivery to Philadelphia. Traveling by rail and steamboat, Brown suffered in his tight quarters but survived to tell his dramatic tale.

The Spy Who Wore Petticoats transports readers to New York during the Revolutionary War, when British troops patrolled areas in Manhattan and Long Island, trying to identify spies who reported to General Washington's staff; Anna Strong was one of those spies. The writing is straightforward, and each book's graphic-novel format features its own color palette and a distinctive style of drawing and character-portrayal. An appealing biography series.