School age, like all other age levels, opens with a critical or turning-point period; this was described in the literature as the crisis at age seven before the other age levels were described. It was noted for a long time that in making the transition from preschool to school age, the child changes abruptly and becomes more difficult with respect to rearing than he was previously. This is a kind of transitional stage—he is no longer a preschooler and not yet a school child.