Unlike traditional books which are passive, the Electronic Book lends itself to dynamic user interactions and is active. Multimedia technology enhances Electronic Books with video, sound, and animation in addition to text. Present generation authoring tools such as Authorware which are used to create multimedia electronic books, are designed as intraframe systems and are limited in their animation capabilities. Our authoring tool design supported by a knowledge base is interframe based which makes animation more realistic. The paper describes animation algorithms developed for such tools. The animation method uses stop points for interpolation and the technique used is a combination of bitblit and real time animation. The software design is object oriented which gives our approach more flexibility.