The Son of Neptune
Rick Riordan
Heroes of Olympus (2)
Project Hail Mary
Andy Weir
The Sea of Monsters
Percy Jackson & The Olympians (2)
Pebble in the Sky
Isaac Asimov
Galactic Empire (3)
Hiking Colorado: A Guide to the State's Greatest Hiking Adventures
Sandy Heise & Maryann Gaug
Hiking through History Colorado
Robert Hurst
Hiking Waterfalls in Colorado
Susan Joy Paul
60 Hikes Within 60 Miles: Denver and Boulder
Kim Lipker
Mountaineering
The Mountaineers