“Protection and Restoration of the Environment” is a well-known series of international conferences, organized jointly by one American and one Greek University every two years. It started in 1992, in Thessaloniki, Greece. The 12th Conference of this series was organized by the Stevens Institute of Technology, USA, the Department of Civil Engineering and the Department of Planning and Regional Development of the University of Thessaly. The conference is designed to encourage the exchange of ideas and knowledge between diverse groups of the scientific community concerned with current issues in protection and restoration of the environment. Participation has been very encouraging. Almost 300 papers have been selected for oral or poster presentation, covering a wide range of topics, and reflecting the interdisciplinary nature of environmental challenges.