This study attempted to estimate by objective means the level of sophistication of high school students' interest in fiction and to determine the degree to which sophistication was related to selected personality factors and to sex, age, intelligence, and reading achievement. A scale was developed to measure sophistication of reading interests; a standardized test was used to measure personality factors. Students in grades 9-12 served as subjects for the study. Findings indicated that, considered in combination, personality variables were not significantly related to sophistication of reading interests, but sex, age, I.Q., and reading achievement were. Considering personality factors singly, benevolence was related to sophistication of reading interests for the total population, and conformity was significantly related for the male population. Sex, I.Q., and reading achievement, considered singly, were significantly related, but age was not. The correlation of a single factor or combination of factors with the sophistication of reading interests was not high enough, however, to be useful in predicting the level of sophistication. (Author/DB)