Selection and appointment of arbitrators is one of the crucial issues of arbitration. Laws and rules applicable to arbitration usually do not impose any special requirements on arbitrators, except eligibility criteria such as a minimum age and requirements of independence and impartiality. The parties may agree on the requirements for arbitrators in the arbitration agreement; an arbitration agreement exclusively results from the autonomy of the parties within the limits determined by the lex arbitri. The parties, however, may not forego the requirements of independence and impartiality. Also, an appointing authority must be fully independent of the parties. Despite the fact that this principle is not explicitly articulated in the laws and rules or any other provisions applicable to arbitration, it is a principle inherent to arbitration and is a manifestation of the principle of equality of the parties, which must be considered the procedural ordre public in arbitration. An arbitrator must always act as a person with no vested interest in the course and outcome of the dispute. The circumstances disqualifying arbitrators must be not only objective but also reasonably evident, and not merely speculative. Impartiality is a highly subjective category and, in relation to bias it might be said that bias establishes the risk of an absence of impartiality.