Reviews the historical evolution of the concept of the Type A behavior pattern (TABP) and evidence for its association with clinical coronary heart disease (CHD). It is suggested that the global TABP is not a reliable predictor of CHD endpoints. However, investigation of various components of the TABP has consistently implicated hostility in the pathogenesis of CHD. Subsequent research has suggested that some facets of hostility may be more "toxic" than others. Recent attempts have been made to incorporate coronary-prone facets of hostility into the agreeableness vs antagonism domain of the 5-factor model of personality.