e.

"Father Brown" had first made his appearance in magazines and these
detective stories became the most purely popular of Gilbert's books.
It was a new genre: detection in which the mind of a man means more
than his footprints or cigar ash, even to the detective. The one
reproduced in most anthologies--"The Invisible Man"--depends for its
solution on the fact that certain people are _morally_ invisible. To
the question "Has anyone been here" the answer "No" does not include
the milkman or the postman: thus the postman is the morally invisible
man who has committed the crime. A thread of this sort runs through
all the stories, but they are, like all his romances, full too of
escape and peril and wild adventure.

Life on several occasions imitated Gilbert's fancies. Thus the Azeff
revelations followed his fantastic idea in _The Man Who Was Thursday_
of the anarchists who turn out to be detectives in disguise. The
technique of Father Brown himself was imitated by a man in Detroit
who recovered a stolen car by putting himself imaginatively in the
thief's place and driving an exactly similar car around likely
corners till he came suddenly upon his own, left in a lonely road. He
wrote to tell Gilbert of this adventure.

From Chicago came an even odder example. "It is extremely difficult,"
wrote the _Tribune_, "to determine the proper relationship of the
Chiesa-Prudente-Di Cossato duels to Mr. Gilbert K. Chesterton's book,
_The Ball and the Cross"_ . . .

The flight in search of a duelling ground; the pursuit by the
police; the friendly intervention of the anarchist wineshop-keeper,
Volpi; the offer of his backyard for fighting purposes; the
unfriendly intervention of the police; the friendly intervention of
the reporters; the renewed and insistently unfriendly intervention of
the police commissioner; the disgust of the duellists; the extreme
disgust of the anarchist; the renewed flight of the fighters,
seconds, physicians, reporters, and the anarchist over the back
fences--all these and other incidents are essentially Chestertonian.

The Di Cossato affair was carried off with fully as much spirit and
dash; with fully as many automobiles, seconds, physicians, reporters
and police, all scampering over the country roads until the artistic
deputy and the aged veteran of the war of 1859, outdistancing their
pursuers, could find opportunity in comparative peace to cut the
gloriou