National Park Thrillers is also celebrating the start of the park system's next hundred years with limited edition commemorative posters. The first called "Defending America's Best Idea" honors real American heroes, the park rangers who everyday preserve and protect our national heritage.
Drawn in the style of the Depression era works progress administration "See America First" park posters, these posters will highlight each month a different aspect of national parks and the values their protect.
Look for the next poster the end of May.
Sean Smith is a former Yellowstone Ranger, and an award winning conservationist, TEDx speaker, and author. He writes national park thrillers from his home in the shadow of Mount Rainier National Park. To learn more about his thrillers click here or follow him on twitter: @parkthrillers