FLM monographs share FLM's goals of stimulating reflection and generating productive discussion in mathematics education. They explore ideas and activities that affect the learning of mathematics. Monographs emerge from discussions among colleagues, so that they have the unity suggested by the label 'monograph' while preserving the diversity of voices that distinguishes FLM. Each has a single theme that connects the chapters, while reflecting a diversity of viewpoints. Suggestions for, and enquiries about, future monographs should be directed to the editor.