In this study of the size of the labor force in the United States during
the wars that began in 1914 and 1939 Mr. Long has made a contribu-
tion of great scientific value. His detailed analysis of the data From
which estimates of this country's working population are commonly
derived not only suggests the limits that the total number of people
available for work imposes upon a nation's war effort but also helps
to answer many questions that have always puzzled students of our
decennial censuses of occupations.

One of the most interesting of his findings is the contrast between
the strain on our labor force in the first and second world wars.
During World War I Mr. Long concludes that net additions to the
normal labor force were "few or non-existent." Presumably losses
to the armed services were then made up by transferring men and
women from non-essential to essential activities. But in this war
the situation has been altogether different. The labor force increased
substantially. "Little or no net increase took place during the two
years before the United States entered the war, despite fuller em-
ployment. During 1942 and 1943, however, there was a rise of nearly
six million men and women, of whom more than four-fifths came in
independently of the growth in working-age population." Of these
nearly five million, "more than two million were women, all but a
quarter of whom were 25 and older. More than two and a half
million were men, all but a fifth of whom were 24 or younger."

As concerns the possibility of further increasing the net labor
force of the United States at present, when our military program
contemplates inducting more than a million additional men and
manpower problems are becoming more pressing in several of our
most important industrial areas, Mr. Long offers little hope. The
only untapped sources of new labor supply are children at school
and women with children under 14. Efforts to draw upon these re-
serves, Mr. Long believes, will encounter strong and effective
resistance. If, therefore, the war goes on and further increases, in the
armed forces are deemed necessary, it may be inferred from these
figures that maintaining, or increasing, war production will require
large transfers from civilian to war work or more hours and harder
work, or both.

No striking difference is observed in the degree to which Britain

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