I took this book on a recent research trip to a preserve near La Selva, and used it daily. Not just a field guide with pretty pictures, this book contains a key to the species. Since it is specific to this area of the country, it cut down on the amount of material that had to be sorted through to ID organisms. I could quickly key out species without having to worry about whether or not this was the right area for that particular species. The photos were clear and beautiful, with different color phases and sexual dimorphisms illustrated. If you are traveling to this specific area of Costa Rica, this book is really useful. It's small, lightweight, easy to use, and CHEAP!