An account is given of a case worker's success in enabling a four-year-old child to separate from his mother for attendance at nursery school. The dynamic factors in the complex relationship of mother and child are discussed on the basis of observation made in twenty-eight interviews. The child's feeling of rejection was understood and handled mainly in terms of his awareness of his mother's motives, while the traumatic factor in his acute anxiety—an earlier hospitalization with phantasies of being abandoned—became known only after treatment had ceased. An attempt is made to estimate the relative decisiveness in the success of the actual interpretative work, the new educational approach offered to the mother, and the modifying influence of the worker's warm personality on the relationship. An interesting reaction by the child to misinterpretation is discussed.