As geochronology has progressed in the last 20 years, the Archean has continued to attract interest. Advancements in our understanding of Archean crustal and mantle evolution can be traced through a series of meetings and published papers beginning in 1970 with the first International Archean Symposium in Perth in Western Australia (Glover, 1970). Among the exciting problems at that meeting were the relationship between low and high grade Archean terrains, the origin of Archean ultramafic rocks and, in particular, the recently discovered komatiites in South Africa, and the origin of various Archean mineral deposits. Only about 30% of the papers dealt with geochronology and Archean crustal evolution.