A major innovation in PISA 2006 was that many of the science units contained one or two questions designed to assess students' attitudes toward science—in particular, students’ interest in learning about specific science topics. In addition, the student questionnaire contained a multipart question to ascertain students’ interest in learning about various broad science topics. This chapter discusses what was learned about which science topics students would like to study from students' responses to these questions, in both the PISA 2006 main survey and field trial.