This monograph provides a conceptual and theoretical framework for the use of hypermedia presentations in the classroom, particularly in the science classroom. Traditional methods of presenting information are linear in nature but research has shown that learning rarely proceeds in a linear fashion. The omni-directional nature of hypermedia presentations has fit quite nicely into the models of learning of some of the most recent cognitive theories. They have been particularly well suited to several important needs for science education. These topics are discussed in relation to some ongoing research projects. (Author/PR)