Any consideration of editorial apparatus is misguided if it loses sight of the convenience of the reader. For some audiences, the apparatus may be irrelevant and need not accompany the edited text; but for most scholarly audiences an edition without apparatus resembles any other work that lacks documentation--it may be brilliantly done, but it provides no aids for facilitating the scholar's independent investigation of the evidence. The apparatus (as the word itself suggests) is a tool for expediting further study, and a tool, to be effective, must be as simple and as easy to use as the circumstances allow. Fredson Bowers--through his connections with editions of Dekker, Beaumont and Fletcher, Fielding, Hawthorne, Crane, and Dewey--has done more than anyone else to set the course of modern apparatus along these lines. As a result of his efforts, there is now not only a widespread acceptance of an efficient basic approach to apparatus but also an increased awareness of the significance of apparatus. Though just a tool appended to a text, the apparatus may well be the only part of an edition that can meaningfully be called "definitive": there may legitimately be differences of opinion about certain emendations which an editor makes, but a responsible apparatus is a definitive statement of the textual situation (within the limits of the copies examined). What constitutes an apparatus responsible in both form and content is therefore a matter worth serious consideration. Only by being fully cognizant of the issues and problems involved in setting up an apparatus can an editor make those decisions which will establish his apparatus as a lasting contribution to literary study.