Lost paperback book 'The Endless Sky' with personal notes, left at a scenic overlook in the High Rockies.

I lost my favorite book, 'The Endless Sky', while hiking in the High Rockies last weekend. I noticed it was missing when I was taking a break at one of the scenic overlooks. It's a paperback with a few pages dog-eared, and it contains some personal notes I've written in the margins. I'm really hoping to get it back, as it's a special gift from my grandmother.