The book "Indians of the Yosemite Valley and Surrounding Areas: Their History, Customs and Traditions" is written by author Gaylen Clark. This book explores the lives of the Native American tribes that once inhabited Yosemite Valley and the surrounding areas. The author tells in detail about the history of these tribes, their traditions, customs, religious beliefs and way of life. The book is a valuable source of information about the culture and heritage of the Indians who lived in this region and helps to better understand their unique history and way of life.