Over the last few years Web Engineering has begun to gain mainstream acc- tance within the software engineering, IT and related disciplines. In particular, both researchers and practitioners are increasingly recognizing the unique c- racteristics of Web systems, and what these characteristicsimply in terms of the approaches we take to Web systems development and deployment in practice. A scan of the publications in related conference proceedings and journals highlights the diversity of the discipline areas which contribute to both the ri- ness and the complexity of Web Engineering. The 5th International Conference on Web Engineering (ICWE2005), held in Sydney, Australia, extends the traditions established by the earlier conferences in the series: ICWE2004 in Munich, Germany; ICWE2003 in Oviedo, Spain; ICWE2002 in Santa Fe, Argentina; and ICWE2001 in Caceres, Spain. Not only have these conferences helped disseminate cutting edge research within the ?eld of Web Engineering, but they have also helped de?ne and shape the discipline itself.TheprogramwehaveputtogetherforICWE2005continuesthisevolution. Indeed, we can now begin to see the maturing of the ?eld. For possibly the ?rst time, there was very little debate within the Program Committee about which papers were in and out of scope, and much more debate as to the each papers contributions to the ?eld.