The author disclaims any pretension to solve all the mysteries of sleep, or give even a precise and scientific explanation of any of them. He aims rather to unsettle, if not dispel, the popular delusion that sleep is merely a state of rest. On the contrary he gives cumulative reasons in support of his theory that no part of our lives is consecrated to nobler or more important uses than that usually spent in sleep. His ultimate purpose is to impart to his readers his own conviction that we are developed spiritually during our sleeping hours as distinctly and exclusively as we are developed physically and intellectually during our waking hours. He declares that were the mysteries of sleep studied with like incentives and by the same class of minds as the mysteries of electricity are now studied, the former would seem to us no more mysterious than the latter, and the results would be no more surprising. Mr. Bigelow has searched history and biography for instances of the phenomena associated with sleep; consequently the book is made unusually readable by the inclusion of numerous illustrative anecdotes.-Book News, Volume 15 [1897]