An intelligent agent and method of negotiating herewith incorporate a number of features, used alone or in combination, to enhance the productivity, security, efficiency and responsiveness of the agent in negotiations with other parties. One feature incorporates randomization of one or more aspects of an agent's behavior to disguise its negotiation strategy from other negotiating parties and thereby prevent such parties from gaining a negotiating advantage at the expense of the agent. Another features incorporates limiting unproductive negotiations by constraining one or more aspects of an agent's behavior based upon the behavior of a negotiating party and/or the duration of the transaction, and thereby making it more likely that unproductive negotiations will be terminated. An additional feature incorporates dynamic value determination to determine the desired value of a desired transaction by weighting and normalizing estimated values retrieved from a plurality of information sources. Moreover, a further features incorporates dynamic value determination which weights and normalizes the values of related transactions based upon the proximity of the related and desired transactions.