''The torture situation is an external conflict, a contest between the subject and his tormentor,'' the manual said. ''The pain which is being inflicted upon him from outside himself may actually intensify his will to resist. On the other hand, pain which he feels he is inflicting upon himself is more likely to sap his resistance.''

So if a subject is ''required to maintain rigid positions such as standing at attention or sitting on a stool for long periods of time,'' the manual said, ''the immediate source of pain is not the 'questioner' but the subject himself.''

This kind of physical and psychological harassment could be combined with ''persistent manipulation of time'' like ''retarding and advancing clocks, disrupting sleep schedules, disorientation regarding night and day'' -- all to the end of breaking the subject's will to resist, to ''drive him deeper and deeper into himself, until he no longer is able to control his responses in an adult fashion,'' the manual said.

Some of the passages in the 1983 manual paralleled some of the milder language from a 1963 C.I.A. guidebook on interrogating suspected spies or Soviet agents. The 1963 text, which was written at a time when the C.I.A. was not subjected to Congressional oversight or outside scrutiny, said approval from headquarters was necessary before a interrogator used physical torture, electric shocks, mind-altering drugs or ''bodily harm'' on a subject.

In 1985, the C.I.A. adopted a formal policy against inhumane treatment during interrogation. It rewrote the manual, deleting or editing its harshest passages. And, in a written statement to its officers and foreign agents, it warned against ''the use of force, mental torture, threats, insults, or exposure to unpleasant and inhumane treatment of any kind as an aid to interrogation.''

''Experience indicates that the use of force is not necessary to gain cooperation of sources,'' the 1985 policy statement said. ''Use of force is a poor technique.'' Force ''yields unreliable results,'' it said, and ''will probably result in adverse publicity and/or legal action against the interrogator.''

''However,'' it continued, ''the use of force is not to be confused with psychological ploys, verbal trickery, or other nonviolent and non-coercive ruses employed by the interrogators in the successful interrogation of reticent or uncooperative sources.''