This study analyzed how one teacher used contemporary children's literature to supplement middle-grades geometry. The teacher's students were matched to students in other classes on general reading, general mathematics, and geometry. Student and teacher interviews, observation notes, and video tape recordings provided insights into fluency and flexibility with mathematical vocabulary. On the three outcome measures, the groups showed little change in general reading and a modest increase in general mathematics abilities. In contrast, the students in the children's literature group showed markedly improved performance in geometry. Analyses indicated these students: (a) showed fluency with geometry vocabulary, (b) demonstrated flexibility in the application of geometry concepts, (c) explained formulae with rich descriptions, and (d) outperformed the non story group on geometry ability when controlling for pretest performance. (Contains 3 tables.)