A curious instance of the advertising value of the mere presence of a public library and of business shrewdness in taking advantage of it, comes from a library that calls itself a “shining example of efforts to ‘work’ public libraries for commercial purposes.” This library rents rooms for various objects connected with its work, and finds that it is in great demand as a tenant. Great effort is made by property owners both to retain and to move quarters occupied for library purposes. The board has recently refused to make selection of localities on this basis. There is another respect in which the public library offers an attractive field for exploitation. In its registration files it has a valuable selected list of names and addresses which may be of service in various ways either as a mailing-list or as a directory. Probably there are no two opinions regarding the impropriety of allowing the list to be used for commercial purposes along either line. The use as a directory may occasionally be legitimate and is allowable after investigation and report to some one in authority. I have known of recourse to library registration lists by the police, to find a fugitive from justice; by private detectives, ostensibly on the same errand; by a wife, looking for her runaway husband; by persons searching for lost relatives; and by creditors on the trail of debtors in hiding. Where there is any doubt, the matter can usually be adjusted by offering to forward a letter to the person sought, or to communicate to that person the seeker’s desire and let him respond if he wishes to do so. One thing is certain: except in obedience to an order of court, it is not only unjust, but entirely inexpedient from the library’s standpoint to betray to anyone a user’s whereabouts against that user’s wishes or even where there is a mere possibility of his objection. If it were clearly understood that such consequences might follow the holding of a library card, we should doubtless lose many readers that we especially desire to attract and hold.