This excerpt taken from the AMZN 8-K filed Sep 18, 2007.
The officers of the corporation shall be a Chief Executive Officer, a President, a Secretary and a Treasurer, each of whom shall be elected by the Board. One or more Vice Presidents and such other officers and assistant officers, including a Chairman of the Board, may be elected or appointed by the Board, such officers and assistant officers to hold office for such period, have such authority and perform such duties as are provided in these Bylaws or as may be provided by resolution of the Board. Any officer may be assigned by the Board any additional title that the Board deems appropriate. The Board may delegate to any officer or agent the power to appoint any such subordinate officers or agents and to prescribe their respective terms of office, authority and duties. Any two or more offices may be held by the same person.