This paper reviews literature and research on the effects of age of initial entry into schooling, citing over 20 studies from the 1930's through the 1970's relating entrance age to academic success and personality development. Studies investigating the effect of early entry into first grade on academic achievement have indicated that not only chronological age, but mental age, adjustment, and I.Q. are determining factors in success. Other researchers have stated that although achievement is related to entrance age, this does not mean that raising the minimum entrance age would prove profitable. Research contrasting children matched on sex, intelligence quotient, socioeconomic status, and schools attended has indicated that children who entered at a later chronological age scored consistently higher on achievement ratings than their younger classmates; another study found that the difference in academic achievement between early and late school starters was not statistically significant. In research on early entry as related to school adjustment, findings reported showed that a greater percentage of children who entered kindergarten or first grade at an early age had adjustment problems compared to later entrants. Another study indicated that earlier entrants had more speech defects, nervous indications, and personal and social maladjustments than did older entrants. Sex differences in the variables influencing adjustment have also been found. (Author/SB)