The Pony Rider Boys in Montana / Or, the Mystery of the Old Custer Trail

The Pony Rider Boys in the Grand Canyon / Or, The Mystery of Bright Angel Gulch

The Pony Rider Boys in the Alkali / or, Finding a Key to the Desert Maze

The Pony Rider Boys in the Ozarks / Or, the Secret of Ruby Mountain

The Pony Rider Boys with the Texas Rangers / Or, On the Trail of the Border Bandits

The Battleship Boys at Sea / Two Apprentices in Uncle Sam's Navy