For the early chapters of this book I have consulted, amongst other authorities, the books mentioned in the bibliography on pp. 251-254. It would, however, be ungracious if I failed to acknowledge my indebtedness to that most readable of historians, Mr. Gribble, and to his books, The Early Mountaineers (Fisher Unwin) and The Story of Alpine Climbing (Nelson). Mr. Gribble and his publisher, Mr. Unwin, have kindly allowed me to quote passages translated from the works of the pioneers. Two friends, experts in the practice and history of mountaineering, have read the proofs and helped me with numerous suggestions.