This is my second copy of this excellent travel study. Colorado geology is fascinating and this book brings it to life. Colorad geology is confusing, and this book helps sort it out. We just finished another trip through the mountains, and this book is dog-eared and worn after constant referece. It gives an excellent background to geology in general, and geologic time and colorado geology specifically. The book then breaks down the several regions of colorado's geology and gives them introductions. The bulk of the book is a blow by blow description and explanation of what you see as you are driving down a particular streach of highway from here to there. Great Book. I want the rest of the series someday.