This excerpt taken from the AMZN 8-K filed Sep 18, 2007.
4.7 Chief Executive Officer
The Chief Executive Officer shall be the chief executive officer of the corporation, shall preside over meetings of the Board and stockholders in the absence of a Chairman of the Board and, subject to the Boards control, shall supervise and control all of the assets, business and affairs of the corporation. The Chief Executive Officer may sign deeds, mortgages, bonds, contracts or other instruments, except when the signing and execution thereof have been expressly delegated by the Board or by these Bylaws to some other officer or agent of the corporation or are required by law to be otherwise signed or executed by some other officer or in some other manner. In general, the Chief Executive Officer shall perform all duties incident to the office of Chief Executive Officer and such other duties as are prescribed by the Board from time to time.