The authors examined the strength of literature circles in developing background knowledge--an acknowledged sticking point in the development of understanding for middle graders--with a special focus on the literature circle role of "investigator," where it is student initiative and not teacher direction that guides comprehension. Observing students who were reading Maniac Magee with a teacher who supported reading in literature circles, the authors concluded that being an investigator allowed students to personally learn about topics, words, and people that were important to understanding the novel, and that by treating the novel as a puzzle to solve, they developed an appreciation for the author's research and skill, broadened their own background knowledge, routinely listened and responded to others in their circle, and developed as critical readers. An added bonus was the development of a home-school dialogue. (Contains 1 figure.)