Psychology and Industrial Efficiency corresponds to a German book, which I published a few months ago, under the title Psychologie und Wirlschaftsleben: Ein Beitrag zur angewandten Experimental-Psychologie (Leipzig: J.A. Barth). It is not a translation, as some parts of the German volume have been abbreviated or entirely omitted and other parts have been enlarged and supplemented. Yet the essential substance of the two books is identical.