Abstract As part of the 1991 Annual Meeting of the AAP G in Denver, Colorado, two sessions titled “Giant Oil and Gas Fields of the Decade 1990-2000” were held. These sessions represented the fourth of a four-decade series, each commemorating important giant discoveries and resulting in the publication of AAP G Memoirs, rich in their geologic detail: • Oklahoma City, Oklahoma, 1968, Memoir 14 ( Halbouty, 1970 ) • Houston, Texas, 1979, Memoir 30 ( Halbouty, 1980 ) • Stavanger, Norway, 1990, Memoir 54 ( Halbouty, 1992 ) • Denver, Colorado, 2001, this Memoir Presentations made in Denver represented case histories of giant fields in 14countries ( Figure 1 ): Colombia, Australia, Kazakhstan, China, Brazil, Algeria, Russia, Indonesia, Mexico, Nigeria, Pakistan, the United States, Angola, and Yemen.