This Small Business Innovation Research (SBIR) Phase I project will develop computer software and a companion textbook to teach modeling of biological problems using a simulation language that is expressed in biological terms. The thrust of the project is to incorporate pedagogical and electronic devices to promote critical thinking skills, thus rising above the drill and practice and tutorial software that comprises the existing market. The open architecture of the software will permit students to challenge assumptions in models, to propose their own hypotheses, and to test these hypotheses by developing their own biological models.