the "boss" who directs them.

The reader can easily see that in all cases where a crime,
such as forgery, is concerned, once the identity of the
criminal is ascertained, half the work (or more than half) is
done. The agencies know the face and record of practically
every man who ever flew a bit of bad paper in the United
States, in England, or on the Continent. If an old hand gets
out of prison his movements are watched until it is obvious
that he does not intend to resort to his old tricks. After
the criminal is known or "located," the "trailing" begins and
his "connections" are carefully studied. This may or may not
require what might be called real detective work; that is to
say, work requiring superior power of deducing conclusions
from first-hand information, coupled with unusual skill in
acting upon them. Mere trailing is often simple, yet
sometimes very difficult. A great deal depends on the
operator's own peculiar information as to his man's habits,
haunts, and associates. It is very hard to say in most cases
just where mere knowledge ends and detective work proper
begins. As for disguises, they are almost unknown, except
such as are necessary to enable an operator to join a gang
where his quarry may be working and "rope" him into a
confession.

Detective agencies of the first-class are engaged principally
in clean-cut criminal work, such as guarding banks from
forgers and "yeggmen"--an original and dangerous variety of
burglar peculiar to the United States and Canada. In other
words, they have large associations of clients who need more