"Cooperative Integrated Reading and Composition"[R] ("CIRC"[R]) is a reading and writing program for students in grades 2-6. It has three principal elements: story-related activities, direct instruction in reading comprehension, and integrated language arts/writing. Daily lessons provide students with an opportunity to practice comprehension and reading skills in pairs and small groups. Pairs of students read to each other; predict how stories will end; summarize stories; write responses to questions posed by the teacher; and practice spelling, decoding, and vocabulary. Within cooperative teams of four, students work to understand the main idea of a story and work through the writing activities linked to the story. A Spanish version of the program is available for grades 2-5. Thirty-eight studies reviewed by the What Works Clearinghouse (WWC) investigated the effects of "Cooperative Integrated Reading and Composition"[R] on beginning readers. One study (Stevens, Slavin, & Farnish, 1991) is a randomized controlled trial that meets WWC evidence standards without reservations. One study (Bramlett, 1994) is a quasi-experimental design that meets WWC evidence standards with reservations. These two studies are summarized in this report. The remaining 36 studies do not meet either WWC eligibility screens or evidence standards. Appended are: (1) Research details for Stevens, Slavin, & Farnish, 1991 and Bramlett, 1994; (2) Outcome measures for each domain; (3) Findings included in the rating for the comprehension domain by construct and findings included in the rating for the general reading achievement domain; (4) Summary of subtest findings for the comprehension domain; Summary of subgroup findings for the comprehension domain; Summary of alternate contrast findings for the comprehension domain; and Summary of alternate contrast findings for the general reading achievement domain. A glossary of terms is included. (Contains 6 tables, 6 endnotes and 2 additional sources.)