"Science Books & Films," the journal of the American Association for the Advancement of Science (AAAS), reviews books for young readers in the sciences to identify winners of these categories: Children's Science Picture Book, Middle Grades Science Book, and Young Adult Science Book. At each age level five finalists are selected for the annual AAAS/Subaru SB&F Prize for Excellence. This January the author's fifth-grade classes are analyzing and evaluating the middle grade finalists. To provide criteria for the evaluation process, the author has used a rubric created by D. Timothy Gerber, associate professor of biology at the University of Wisconsin-LaCrosse, and some of the thinking routines learned in the Project Zero Institute at Harvard Graduate School of Education. Thinking routines are approaches to instruction that foster a culture of thinking within the classroom--and help develop good thinking dispositions among students. This article details how the author used thinking routines to help students evaluate these science books. (Contains 1 figure.)