This chapter charts the development of the three phases of the Georgia Centenarian Study (Poon, 1992). The goal of this chapter is to share rationale, methodologies, design pitfalls, and strategies in studying centenarians. A fundamental challenge for all centenarian studies is to understand how centenarians live longer and to identify the specific biological, psychological, and sociological characteristics that make this possible (Lehr, 1991; Poon, Bramlett, Holtsberg, Johnson, & Martin, 1997; Vaillant & Mukamal, 2001). Studies of centenarians and the oldest old remain, in relative terms, a rarity within gerontological research (Vaupel et al., 1998), although interest in this area has increased steadily over the past 20 years (Lehr, 1991; Poon et al., 1997; Vaupel et al., 1998). Studies conducted in the United States (e.g., Perls, 1997; Poon, 1992), Japan (e.g., Chan, Suzuki, & Yamamoto, 1997), South Korea (Wilcox, Wilcox, & Suzuki, 2001), Italy (e.g., Capurso et al., 1997), Hungary (e.g., Regius, Beregi, & Klinger, 1994), France (e.g., Regius et al., 1994), Sweden (e.g., Samuelsson et al., 1997), Finland, and Denmark (Jeune, 1994) have added greatly to our knowledge base and provide a foundation for further hypothesis testing and an increasingly realistic and detailed picture of what it is like to be 100.