Petros P. Xanthakos is a consulting engineer in Virginia. A Ph.D. in civil and structural engineering, Dr. Xanthakos is widely considered a top authority in the technology of bridges and underground construction. His previous books include: Slurry Walls, 1980, McGraw-Hill, 680 pp.; Ground Anchors and Anchored Structures, 1991, Wiley, 685 pp.; Theory and Design of Bridges, 1994, Wiley, 1443 pp.; Slurry Walls as Structural Systems, 1994, McGraw-Hill, 855 pp.; Ground Control and Improvement, 1994, Wiley, 910 pp.; Bridge Substructure and Foundation Design, 1995, Prentice Hall, 844 pp.