Organized in three sections, this report presents the first case study from a project aimed at developing prototypes of ideal textbook chapters. The report (1) discusses the Ideal Text Project, in which a number of researchers in instructional science have been challenged to design a textbook chapter that incorporates the design features they think an ideal text should contain; (2) includes the first prototype chapter developed (a tenth grade biology text chapter on the brain); and (3) presents extensive commentary on the development of the chapter, including the text design framework, and text design features. (HOD)