I bought this book when we first moved to this mountain a mile in the air. It was a lifesaver! The authors know what they're about when it comes to high-altitude cooking. And, in the back of the book, there's a list of all the cities in the world that qualify as "high-altitude", so you can send your high-living friends a copy.
A bit dated... but really effective. Recommend having it on hand. Could use more photos as modern cookbooks go though!