Countertransference can be a personal disturbance or a useful tool in understanding and interpreting. In 'normal countertransference' there is rapid oscillation between introjection and projection, the patient receiving effective interpretations. In a disturbed situation, however, there may be symbiosis: the analyst prolongs the introjection of the patient he is unable to help, the patient projects parts of himself onto the analyst (as Melanie Klein believes). Here the analyst is hampered by insufficient self-understanding. It is most important to be able to discriminate sharply between two similar things: one's own ineptness at a given moment in analysis, and the patient's awareness of this and his contempt for that part of himself projected onto the analyst. Money-Kyrle describes other conditions that disturb 'normal countertransference', particularly the patient's use of projective identification, and tells how to cope with them.