Of the world’s famous mountain ranges, the Sierra Nevada is one of the most spectacular in the number and variety of its lakes. From Lassen Peak in the north to Mount Whitney in the south, the crest and Banks of the great barrier are flecked with the blue of thousands of them—there are 429 in Yosemite Park alone, and in a single area of 220 square miles at the southern end of Lake Tahoe there is a galaxy of more than a hundred. These ice-blue pools lie casually in the most unexpected places—in bleak cirques well above timber line, in river bottoms, in densely timbered canyons, and on the summits of boulder-strewed passes. They range in size from navigable bodies of 300 square miles to small glacial ponds of a few acres. Almost every imaginable geologic origin is represented somewhere among them, as well as some unimaginable freaks of contour. As John Muir was probably the first to point out, theirs is the charm of the unpredictable. Around them centers much of the history of California and Nevada, and until now no comprehensive effort has been made by anyone to narrate it. Dr. and Mrs. Hinkle, who are well-nigh ideally equipped to delineate the fascinating history of the Sierra lakes and their near-lying Great Basin neighbors. Both are the descendants of long lines of pioneer forebears. Both were born and grew up in Truckee, the main gateway of the transcontinental route between Nevada and California. Both are inheritors of a great love for the region and of a great mass of family and traditionary lore concerning it. Both are trained in the employment of bibliographical and historical tools for the writing of history. Finally, as husband and wife, they constitute a well-geared, smoothly functioning literary team, each member of which reinforces and supplements the labors and perceptions of the other.