Can digital libraries provide a reading experience that more closely resembles a real book than a scrolled or paginated electronic display? This paper describes a prototype page-turning system that realistically animates full three-dimensional page-turns. The dynamic behavior is generated by a mass-spring model defined on a rectangular grid of particles. The prototype takes a PDF or E-book file, renders it into a sequence of PNG images representing individual pages, and animates the page-turns under user control. The simulation behaves fairly naturally, although more computer graphics work is required to perfect it.