The study of "Thinking Reader"[R] is a multisite cluster randomized controlled trial. Ninety-two reading/English language arts teachers from 32 elementary and middle schools were randomly assigned within their schools to either the "Thinking Reader"[R] condition or the comparison condition. The analysis sample consisted of 90 classes and 2,147 grade 6 students, with 1,156 students in the "Thinking Reader"[R] condition and 991 students in the comparison condition. Teachers in the "Thinking Reader"[R] condition supplemented their regular English language arts or reading instruction with one to three preselected "Thinking Reader"[R] novels that students were asked to read within the "Thinking Reader"[R] software program. Students in comparison group classrooms participated in the schools' regular curriculum. The study assessed the effectiveness of "Thinking Reader"[R] by comparing the reading comprehension of students in the "Thinking Reader"[R] and comparison conditions at the end of the school year. The study found no statistically significant differences on the comprehension outcomes of students in the "Thinking Reader"[R] classes, compared with students in the comparison classes. The research described in this report meets What Works Clearinghouse (WWC) evidence standards without reservations. Appended are: (1) Study details; (2) Outcome measures for each domain; (3) Study findings for the comprehension domain; and (4) Subgroup findings for the comprehension domain. A glossary of terms is included. (Contains 6 endnotes.) [The following study is the focus of this "Review": "Impact of the Thinking Reader[R] Software Program on Grade 6 Reading Vocabulary, Comprehension, Strategies, and Motivation: Final Report. NCEE 2010-4035" (ED517968).]