The trend in many classrooms is to move away from using a single textbook in content area classrooms and move toward the use of various works of children's literature integrated with and related to a content-area topic. Instead of using a single discipline approach, teachers should use a multidisciplinary approach in which several subject areas can be integrated using a central theme. Although textbooks provide helpful organization features for reading, their "dry" collection of facts many not motivate students to read. In most cases the teacher designs thematic units which provide opportunities for the students to read extensively in trade books related to the chosen topic. Thematic units can be effectively used at the middle and upper grades because at these levels the content subjects, especially social studies, math, and science have specific concepts to be learned. Thematic units developed by the teacher need to include content area information which will allow students the opportunity for an in-depth learning of specific information. Teachers can develop the units themselves, or the teachers can brainstorm (perhaps using a webbing technique) with students on how skills can be mastered. Interdisciplinary units (which are even more time consuming than a thematic unit) may be organized by using a block plan. Experiences in using thematic units has led to the conclusion that these units offer students the motivation and interest in learning content subjects. (Contains 25 references, a web outline, and a block plan for a unit on weather.) (RS)