The theme of this proceedings, Extreme Tunneling: Improving Progress, Cost, Performance, and Safety, was chosen to emphasize a number of significant milestones in underground construction, with particular reference to reduction of costs and to improvements in health and safety. The papers are grouped here under four main headings:

• Management of Underground Projects
• Public Policy and Underground Facilities
• Advances in Tunneling Technology
• Case Histories: The Trials, Tribulations and Triumphs of Underground Construction.

This work will be of interest to those involved in infrastructure development, tunneling, underground construction and other uses of underground space. Includes a cd-rom of the proceedings.