Although the polygraph is useful in determining the presence of physiological changes (changes in heart rate, perspiration, and respiration), it cannot provide reasons for the changes, which might include embarrassment, anger, resentment, or other feelings. It has been determined that there is no one specific physiological lie response. The primary value of the polygraph is in its use to solicit admissions of guilt. Most of the admissions result from the subject's being convinced of the infallibility of the polygraph. There appear to be four situations where the legal profession may find the polygraph useful: (1) when the defense counsel wants to know whether his/her client is telling the truth, (2) when the defense counsel wants to use favorable polygraph results to persuade the prosecutor not to seek an indictment, (3) when the defense and the prosecutor agree to use polygraph results as the basis for how to proceed in case processing, and (4) as an investigative aid to verify a witness' statement or the suspect's denial. There are still too many unanswered questions about the polygraph's ability to permit its widespread use in the courtroom. These questions will not soon be resolved. Meanwhile, attorneys should carefully observe the evolving use of the polygraph and use it carefully for a client's best interests.