This present study sought to evaluate the effectiveness of two types of school library displays: a display with books only, called Display, and a display with books, posters, models, copy, and realia, called Display +. The effectiveness of these displays was to be measured in two ways: a) through the observation of the attaction power, holding power and viewer participation in a display and b) through measuring the circulation of displayed books. Before commencing the study a literature search was conducted. The result of the literature search yielded four authors, Goldhor (1972; 1981), Aguilar (1983), Watson (1985), and Baker (1986), who had researched the relationship between circulation and displays. Each of these studies used the measurable effect of circulation increasing, decreasing or remaining constant to determine the effect of the display. This present study used a similar methodology and monitored the circulation of books on both types of displays. However, this study sought to go beyond the effect of circulation in determining the effectiveness of displays because the previous studies had not taken into account the library user who is affected by the display but is unable to borrow a book from the display. The literature search turned towards the area of museum exhibits and displays and the methodology employed to evaluate these exhibits and displays. Shettel (1968), Warren (1972), Screven (1976), Linn (1976), Clowes and Wolfe (1980), and Miles (1982) used attraction and holding power as measures of museum exhibit and display effectiveness. Similarly, library users can be attracted and their attention held by library displays. To the variables of attraction and holding power this study added the variable of participation, picking up books or other items in the display not necessarily with the intent of borrowing the books. In order to construct a Display + and control as far as possible the elements in the display a literature search of books and articles relating to the design elements of displays was conducted, and findings applied in the construction of the display. Shettel's (1968) methodology of unobtrusive observation was employed in this study with the added benefit of videotaping the observations. The hypotheses were set out in three groups, those relating to a single display, those comparing the effectiveness of Display and Display +, and those relating to circulation. The results of this study found in general that the attraction power of Display + exceeded the attraction power of Display but the holding power and participation in Display was greater than that of Display + indicating that the designer of library displays should pay particular attention to the purpose of displays in their libraries. The results of the circulation hypothesis confirmed the results of Goldhor (1972;1981), Aguilar (1983), Watson (1985), and Baker (1986) that more books circulated when they were displayed than when they were on the library shelves.