Proceedings of sessions of Geo-Congress '98, held in Boston, Massachusetts, October 18-21, 1998. Sponsored by the Geo-Institute of ASCE. This Geotechnical Special Publication contains 10 papers focusing on innovations in design and construction of earth-retaining systems, design criteria, specialty testing programs, and instrumentation monitoring. Most papers focus on the design and construction aspects of various segments of the Central Artery/Tunnel project in Boston, including: proposed soil-cement mixing in the Fort Point Channel; design of the jacked tunnels that run underneath railroad tracks leading to South Station; instrumentation used on a project-wide basis with emphasis on the soil-mix and jacked tunnel sections; base stability issues and effects of soil-cement treatment; design and performance of a tied-back sheet pile wall in soft clay; and a case study of a Casting Basin. Other papers describe anchored, deep soil-mixed cutoff walls and design-build tied-back walls in Wisconsin; the use of soil nails in soft clay; deep excavations in Berlin, Germany; and precast, prestressed slurry walls.