The files--immense, dirty brown covered albums--each containing 6,000 photographs--overflow through room after room and corridor after corridor. There are smaller volumes with duplicate photographs, 500 in each, which give particulars of marks or physical peculiarities. Hundreds of thousands of records are kept, mostly illustrated by the inevitable full and side face photographs, and each is kept up-to-date with scrupulous care. The Convict Supervision Office, with its subsidiary Habitual Criminals Registry, has within the last year or two been amalgamated with the Finger-print Section under the general title of the Criminal Record Office. Although the two departments work in unison and are, to a certain point, interdependent, their work has to be conducted in sub-departments. The Habitual Criminals Registry--I retain the old title for convenience--is a sort of British Museum of crime. It is a central bureau that is constantly being consulted from all parts of the kingdom, and not seldom from all parts of the world. It has to be ready at any moment to lay its hands on the record of any criminal that may be demanded, and in this it is immensely helped by the Finger-print Department, which can usually identify the person and supply the number by which he is known. It sometimes happens, however, that no finger-prints are available. Then search has to be made under the old system. The records are grouped by the height of their subjects and the colour of their eyes and hair. Thus, if a prisoner on remand is five feet nine, with blue eyes and brown hair, the margin of search is limited to those indexed under those characteristics. The records include photographs, descriptions, and particulars not only of licence-holders and supervisees, but of every person who has been convicted twice or more times of any crime, with a few exceptions, and of all persons sentenced to hard labour for a month or more. They are a veritable "Who's Who" of the criminal world, and go even further than that useful work of reference in supplying intimate details of the appearance and idiosyncrasies of their subjects. But the keeping of recidivist records is only one part of the business of the Criminal Record Office. This is the department which is responsible for keeping a watchful eye on those people the public love to call "ticket-of-leave men," but who are officially known as licence-holders or supervisees. These are convicts who, through good conduct in prison, have been released before the expiration of the full term of their sentence, or persons ordered at the time of their conviction to undergo a period of police supervision after they leave prison. This class is composed very largely of an elusive gentry, and to keep track of their comings and goings is no simple matter when they have reason to vanish for a season.