The Left Behinds: Abe Lincoln and the Selfie that Saved the Union, by David Potter, (2016, 304 pages, Lexile 620) would be the perfect book to pair with Flashback Four #1: The Lincoln Project. (my review). The kids in this second book in The Left Behinds series go to the Civil War battle of Gettysburg, while in The Lincoln Project the kids have an important job to do during the delivery of the Gettysburg Address. The Gettysburg Address was given four and a half months after the battle. Both books were published in 2016 and have many contemporary references such as cell phones, both are chock-full of historical tidbits, really funny, and likely to appeal to both genders. They are at about the same reading level, although The Left Behinds is quite a bit longer.

Summary from goodreads:

Mel, Bev, and Brandon—the Left Behinds—are at it again. When the iTime app on their phones sends them to Washington, D.C., in 1863, they find themselves smack dab in the middle of the Civil War. They sit in on a séance with First Lady Mary Todd Lincoln and are shown every inch of the White House by Tad, the youngest Lincoln. When they drop in on the president himself, Abe Lincoln, he is preoccupied with the fateful battle at Gettysburg, which is just under way.
The kids receive their marching orders—they must somehow travel to Gettysburg from D.C., make sure what’s supposed to happen does happen, save the Union, and be home in time for dinner.
No biggie. After all, it’s only the entire future of the country at stake.
This sequel to The iPhone That Saved George Washington includes an author’s note and information on Civil War reenactments and living history sites around the nation.

Like the first book in the series, The iPhone that Saved George Washington (my review), this one is written from the point of view of Mel, in a light, conversational style. The kids cover a lot of ground in this story. At the White House, they participate in a séance with Mrs. Lincoln, make deals  with Lincoln’s unruly son Tad, and learn how a telegraph machine works. Later, they ride on horses, ride in a cart, ride on a train, and crawl through a couple of dark tunnels. I actually would have preferred that the author cut something to streamline the plot a little more. I did appreciate that the author recognized the role of women in the war effort by having the Southern New Jersey Nurses’ Auxiliary make an appearance. An excerpt:

“What the…,” says Bev. She points her fingers to the road. We see …not only three donkeys, but also two horses, four mules, carts, wagons, and  long double line of ladies.
You heard me right.
Ladies. Not soldiers. Not men or boys. Ladies, or maybe I should say women, though they really do look like ladies to me.
Each one is wearing a long black or brown dress, and, or course, a hat. Even though it’s July and a hundred and two degrees.
And each one is walking very determinedly and, I’d say, also very properly. No slouching, no shuffling.

If you just can’t get enough about Gettysburg:

Related post: Time Travel with President Lincoln. For links to new middle grade book reviews, check out Shannon Messenger’s Marvelous Middle Grade Monday post.