An Undivided Union is the sixth and last volume of the Blue and Gray — on Land series. Like its predecessors, the book follows the adventures of the Riverlawn Cavalry, a Union regiment, raised in Kentucky and participating in the daring campaigns undertaken by the Army of the Cumberland. As in the previous tales of this series, Deck Lyon again comes to the front as the boldest hero, but his achievements come in second to his foster brother. This is a story about people on opposite sides of the war who are not willing to yield each other.
The outline and incomplete material of "An Undivided Union" were left among the papers of the late William T. Adams ("Oliver Optic"), and the same notes that were to complete the "Blue and Gray On Land" series also closed the life-work of one of America's best-known writer of young adult stories. The book was completed by Edward Stratemeyer.
William Taylor Adams (1822 – 1897), pseudonym Oliver Optic, was a famous academic, author, and a member of the Massachusetts House of Representatives. Adams wrote over 100 books, most of them for a young-adult audience.
