The antisocial personality is typed as grossly selfish, callous, irresponsible, impulsive, and unable to feel guilt or learn from experience and punishment. It is estimated that 40 percent of all criminals are antisocial personalities and commit 80 to 90 percent of all crimes. While the antisocial personality has not internalized ethical values, he does understand their effect in others; he will typically manupulate people based on how they will react to certain situations. The words and actions of the negotiator should be carefully chosen to avoid any appearance of an ego threat to the antisocial hostage-taker. Further, the negotiator should avoid any appearance of indecision or ambivalence, since the antisocial personality is adept at manipulating flexible situations. It is important that the authorities provide as much external structure as possible to the situation, without introducing any element of structure they are unwilling to maintain under pressure from the hostage-taker. Authorities should consider the influence of ego stimulation and ego threat on the antisocial personality and should avoid a display of force. It may be helpful in building rapport to match negotiator and subject as to race, religion, nationality, and education. Any attempts by the negotiator to play the role of therapist may be dangerous, as the antisocial personality may respond in the role of patient to achieve his own ends. The negotiator should not count on the hostage-taker forming any emotional attachment to his hostages. Therefore the passage of time does not necessarily serve the hostages' safety. In the negotiator's favor is the antisocial personality's relative lack of anxiety, optimism, and superior intellect, which may prevent him from panicking due to simple negotiating or tactical errors on the part of the authorities. References are provided.