X 
INTRODUCTION 
employment manager has some principles of selection 
which operate in advance of an actual trial. Among 
these means of provisional selection or limitation of the 
numbers for actual trial, objective measurements of the 
candidate’s abilities and achievements and aptitudes are 
being adopted rapidly by progressive employers. Among 
such objective measurements, those devised by psycholo 
gists have recently attracted special attention by their 
promise of special usefulness. They seem destined to 
save time, trouble, and money in many cases. 
Dr. Link’s book is important because it gives an honest, 
impartial account of the use of psychological tests under 
working conditions in a representative industry. He has 
the great merit of writing as a man of science assessing 
his own work, not as an enthusiast eager to make a market 
for psychology with business men. Indeed the story of 
his experiments is distinctly conservative, for in many 
cases he could have obtained an even better prediction 
of success at a given job than he did obtain, by applying 
the technique of partial correlations and the regression 
equation so as to obtain a weighted composite score from 
a team of tests. 
Dr. Link’s book also gives much valuable detail concern 
ing the practical arrangements for investigating the merits 
of tests and for putting satisfactory ones into operation. 
It will be read with interest and profit by students of 
psychology and of business and industrial efficiency. 
Edward L. Thorndike. 
1 Teachers* College, Columbia University.