Practice and Theory of Automated Timetabling VThisvolumecontainsaselectionofpapersfromthe5thInternationalConference on the Practice and Theory of Automated Timetabling (PATAT 2004) held in Pittsburgh, USA, August 1820, 2004. Indeed, as we write this preface, in the Summer of 2005, we note that we are about one month away from the tenth anniversary of the very ? rst PATAT conference in Edinburgh. Since those very early days, the conference series has gone from strength to strength and this volume