Narrator Mark Turetsky manages this juggling act with aplomb... Turetsky’s characterizations of the four teens are spot-on.
— AudioFile Review

The Lincoln Project: The Flashback Four #1

From the publisher:

Congratulations! You are invited to participate in a very special once-in-a-lifetime experience. Please do not share this invitation or discuss it with anyone.

In New York Times best-selling author Dan Gutman's all-new series, which blends fascinating real history with an action-packed and hilarious adventure, four very different kids are picked by a mysterious billionaire to travel through time and photograph some of history's most important events. This time the four friends are headed to 1863 to catch Abraham Lincoln delivering his famous Gettysburg Address. They'll have to work together to ask the right questions, meet the right people, and capture the right moment. And, most important - not get caught!

The Titanic Mission: Flashback Four, Book 2

From the publisher: 

In New York Times best-selling author Dan Gutman's all-new series, which blends fascinating real history with an action-packed adventure, four very different kids are picked by a mysterious billionaire to travel through time and photograph some of history's most important events.

This time, Luke, Julia, David, and Isabel are headed to the deck of the doomed Titanic. Their mission? Capture a shot of the sinking ship, then come right back. The only problem is, once they arrive aboard the ship, the four friends can't agree on what to do next. Should they try to save the passengers? Or maybe bring back a priceless book before it sinks with the ship?

The Titanic Mission tells the story of the ship's fateful last voyage like you've never heard it before.