All traits were not created equal. -WORCHEL AND COOPER (1983, p. 180) This book reports the findings from extensive cross-cultural studies of the relative importance ofdifferent psychological traits in 20 countries and the relative favorability of these traits in a subset of 10 countries. While the work is devoted primarily to professionals and advanced students in the social sciences, the relatively nontechnical style - ployed should make the book comprehensible to anyone with a general grasp of the concepts and strategies ofempirical behavioral science. The project grew out of discussions between the first author and third author while the latter was a graduate student at Wake Forest University, U.S.A., in 1990. The third author, a native of Chile, was studying person-descriptive adjectives composing the stereotypes - sociatedwiththe Chilean aboriginal minority knownas Mapuche (Saiz &Williams, 1992). Asweexaminedthe adjectives usedinthisstudy,it was clear that they differed in favorability and also on another dim- sionwhichwe latertermed psychologicalimportance, i.e., the degree to which adjectives reflected more central, as opposed to more - ripheral, personality characteristics. More important descriptors were those which seemed more informative or diagnostic ofwhat a person wasreally like and, hence, might be ofgreater significance in und- standing and predicting an individual’s behavior.