=Follow-up Systems.= A necessary and very important factor in the success of a business transacted through the mails, is the follow-up system. And in a business in which sales are made by personal salesmen, the follow-up is used for certain purposes, and is as important as though used to secure orders. To follow-up is to keep after, to keep in touch with, and to keep a certain subject before certain individuals. Whether used to secure orders or make collections, the idea of the follow-up is the same, though it is better known as a system for promoting sales. The follow-up arises from the same necessity that compels the personal salesman to call on a prospective customer more than once--often many times--before the first order is secured, and continue to call to hold his trade. The follow-up simply makes use of letters and other literature to take the place of the personal salesman. Mechanically, the follow-up system is a _system_ or _method_ that insures the sending of the right literature at the right time. Letters--both form and special--catalogs, booklets, folders, circulars, and mailing cards are all used in the process of following up the prospective purchaser; the automatic method of showing when each piece of literature in the series should be sent, is the follow-up system itself. [Illustration: Fig. 23. Vertical File Drawer Equipped as a Tickler] _Tickler Method._ The simplest method of handling the follow-up system is to use a tickler in which to file memoranda or correspondence by dates. A tickler consists of a file equipped with a set of indexes numbered from 1 to 31 to represent the days of the month, and 12 indexes printed with the name of the month. The monthly indexes are arranged in order, and the daily indexes are placed in front of the monthly indexes in numerical sequence. The file may be a vertical correspondence file, a card tray, or a flat desk file. In using the tickler for a correspondence follow-up, letters are filed back of the index representing the day on which the subject is to receive attention. Each day the letters filed behind that day's index are removed, and after receiving attention, are filed ahead to the next follow-up date. If it is desired to have a letter come up for attention in another than the current month, the day of the month is noted on the letter, and it is placed back of the monthly index. On the first of the month, the index for the previous month is placed at the back of the file, which brings the current month's index to the front. All papers that have been filed back of the monthly index are then distributed by dates. A correspondence file drawer, equipped as a tickler, is shown in Fig. 23.