(12) Using the results from a prior NSF project that developed an inquiry-based curriculum (Living by Chemistry) and a criterion referenced assessment system (ChemQuery), the PI is studying how to design a textbook that builds upon and enhances the benefits of guided-inquiry instruction. The intellectual challenge being addressed is the creation of a textbook for use as a reference that best enhances students' learning in an inquiry-based classroom without preempting the discovery aspect of the pedagogical model. Prototype textbook chapters are being developed to study how students and teachers use the prototypes. The textbook chapters are being developed to: (1) give clear answers while demonstrating the kind of questions that led to those answers; (2) use familiar macroscopic contexts as pedagogical frames without displacing or diluting content; and (3) provide illustrations to bridge the cognitive gulf between the concrete world of macroscopic experience and the abstract models of the particulate theory of matter. Particular attention is being given to the use and effectiveness of illustrations. The effectiveness of the prototypes in improving student understanding is being monitored using ChemQuery.