I owned this book around 1950 when I would have been 7 or 8. This was a thin book of a somewhat large format (8 x 10?), with dark blue cloth covers. The book was primarily text, with occasional full-page lithographed full color paintings. I am pretty sure the title contained the words “Cliff Dwellers”. It was about the “Anasazi” Indians of the Southwest (probably based on Mesa Verde), and was a fictional story involving two children (twins?) and their daily lives, finding water, helping harvest corn, and, what I most remember, negotiating the ladders to and from their cliff dwelling. I’ve searched the LOC on-line catalog, WorldCat, and Abebooks.com, with no success. Hope someone remembers this book.