PREFACE a
tific vocational guidance cannot function without a knowledge
 of the abilities required for the different occupations
and of the methods for measuring these abilities.
Studies carried on with the technique here outlined will
therefore be of value not only to employer and applicants,
but also to those who give vocational and educational counsel,
 since these researches add to available knowledge of
means for measuring vocational aptitude and of the requirements
 for success in the occupations studied.
We are happy to acknowledge our obligations to numerous
investigators in industry and in the universities, both here
and abroad. Many are mentioned in the text or in the
bibliography. In particular we think of the pioneers in personnel
 research who were at the Carnegie Institute of Technology
 for shorter or longer periods between 1915 and 1923,
during the presidency of Dr. A. A. Hamerschlag: Professors
Scott, Miner, Thurstone, Whipple, Gordon, Charters,
Yoakum, Strong, Stevenson, Lovelace, Schoen, Kenagy,
Craig, and their associates and students, including, among
many others, Doctors Beatty, Ruml, Hansen, Robinson,
Bills, Moore, Ream, and Manson. They have shared in the
evolution of this manual. For reading the manuscript and
offering sound suggestions, we are grateful to Professors
E. L. Thorndike and A. W. Kornhauser.
For permission to reproduce tables or charts, we are
indebted to Doctors Thurstone, Kelley, Scott, and Moede,
the Adjutant General of the United States Army, the Life
Insurance Sales Research Bureau, the Dennison Manufacturing
 Company, the General Electric Company, the Macmillan
 Company, the World Book Company, the Popular
Science Monthly, and the Journal of Applied Psychology.
WarLTter VAN DYKE BINGHAM
Max FrevD
New York, July 26, 1926

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