"Altogether an admirable piece of art worked in the spirit of a thorough artist. Every reader of cultivated tastes will find it a book prolific in entertainment of the most refined description, and to all such we commend it heartily."—Boston Saturday Evening Gazette.

"The strange central idea of the story could have occurred only to a writer whose mind was very sensitive to the current modern thought and progress, while its execution, the setting it forth in proper literary clothing, could be successfully attempted only by one whose active literary ability should be fully equalled by his power of assimilative knowledge both literary and scientific, and no less by his courage and capacity for hard work. The book will be found to have a fascination entirely new for the habitual reader of novels. Indeed, Mr. Crawford has succeeded in taking his readers quite above the ordinary plane of novel interest."—Boston Advertiser.