This is a set of 18 matching hardcover Zane Grey novels. Two of the books show water damage on the some of their pages, but the majority of the books are in great shape. The titles include the following:
Riders of the Purple Sage
The Call of the Canyon
Robbers' Roost
The Vanishing American
Twin Sombreros
Wildfire
The Mysterious Rider
Fighting Caravans
Wild Horse Mesa
Shadow on the Trail
Arizona Ames
The Dude Ranger
West of the Pecos
Rogue River Feud
Desert Gold
30,000 on the Hoof
The Thundering Herd
The Lone Star Ranger