The author obtained his Ph.D. from the University of Berlin. He worked for the University of Berlin, the University of Göttingen, . . . . He was regarded as a leading number theorist in those days. The translator worked for the City College of New York.
Certainly no clearer treatment of the foundations of the number system can be offered . . . one can only be thankful to the author for this fundamental piece of exposition, which is alive with his vitality and genius. (American Mathematical Monthly)