Many times when the author saw the bedouins of southern Sinai excavate their wells in the crystalline rocks, from which this part of the peninsula is built, the story of Moses striking the rock to get water came to mind. The reader will, indeed, find in this book the description for a rather simple method by which to strike the rock to get water in the wilderness of Sinai. Yet this method was not invented by the author nor by any other modem hydrogeologist,...