ASTM Committee D18 was formed in 1937. D18 meets twice a year, always in January and June, with about 150 members attending over four days of technical meetings capped by a symposium on relevant topics in the Geotechnical or Geoenvironmental industry. The Committee, with a current membership of 1144, has jurisdiction of 343 standards, published in the Annual Book of ASTM Standards, Volume 04.09. D18 has 20 technical subcommittees that maintain jurisdiction over these standards. Information on this subcommittee structure and D18's portfolio of approved standards and Work Items under construction are available from the List of Subcommittees, Standards and Work Items below. These standards have and continue to play a preeminent role in all aspects important to the effective standardization for the geotechnical and geoenvironmental industries.