The idea for this project grew out of a conversation between Jens Timmermann, Steve Engstrom and Andrews Reath at a conference on Kant's moral philosophy hosted by Peking University in May 2004. We believe that Andy suggested that there was a need for a volume of new essays on the Critique of Practical Reason, and Jens suggested that we assemble a group that would read through the Critique together before embarking on the essays. This volume is thus part of a larger project that included a working group that met several times. Jens Timmermann kindly agreed to host meetings of the group at the University of St Andrews, and we met there twice – in July 2006 to read the Critique together and in late August–early September 2007 to discuss preliminary versions of the papers. Pauline Kleingeld invited us to meet at Leiden University, and we convened there a third time in June 2008 to discuss penultimate versions of the papers. We received financial support from several institutions along the way. We should like to thank Cambridge University Press, the University of St Andrews, the Paton Fund, the Scots Philosophical Club, the University of California at Riverside, the Philosophy Department of Leiden University and the Leiden University Fund. We should also like to thank Lucy Richmond (St Andrews) for compiling the index.