The Comprehensive School Mathematics Program (CSMP) has developed a series of lessons based on what they call detective stories. These lessons all follow the same basic format. A first clue is given, which is appropriate to the selection of a subset of the whole numbers. This is followed by a sequence of further clues, each of which narrows down the choices untill, eventually, a single number is selected. We have observed several of the problem-solving lessons being taught by CSMP teachers in the Clarksv ill e-Montgomery County School System (Tennessee) and found that students reacted enthusiastically to this approach. These lessons were all done with large-group format and were teacher directed. Unfortunately, it is quite difficult to adapt the lessons for use in standard classrooms, since the CSMP lessons make rather extensive use of clues involving the mini-computer and most elementary school students are not familiar with this device. As a result, we decided to write our own detective stories for a third grade class. Our format was different in that we used a learning-center approach and our subject matter was geometry. The remainder of this paper is devoted to a description and evaluation of our detective stories.