A majority of the chapters in this book first saw the light of day as talks at a conference organised and held at Queen’s University in Kingston, Ontario, Canada in April 2001. This small, invitational meeting, tellingly entitled Beauty and the Mathematical Beast, brought together a range of academics int- ested in and committed to exploring connections between mathematics and aesthetics. The enthusiastic response of participants at this gathering enco- aged the presenters to expand upon their initial contributions and persuaded the organisers to recruit further chapters in order to bring a greater balance to the whole. The timing of this event was not arbitrary. The preceding decade had seen a resurgence in serious writing dealing with deeper relations between mathematics (and science) and ‘the beautiful’. In many ways, we the editors of this volume found these contributions to the literature were revisiting and drawing on themes that had been prominent over two thousand five h- dred years ago, in certain writings of the Pythagoreans. While not intending to offer a historical reappraisal of these ancient thinkers here, we have none the less chosen to invoke this profound interweaving of the mathematical and the aesthetic to which this reputedly secretive philosophical sect was ext- sively attuned. This book is divided into three sections comprising three chapters each, each with its own short introduction discussing the particular chapters within.