Who is George Mitchell?

(24[A]) Northern Ireland peace talks resumed yesterday with negotiations under orders from the US Chairman George Mitchell, former US Senator, (23[C]) to stop haggling and get down to the business of solving the worst violence in the province,
   "The time has come to get down to serious negotiations and not to waste your time on full stops and commas. There is an urgent need for this process to proceed." George Mitchell said.
The talks, launched with fanfare by the British and Irish governments in June 12, started, however, without representatives of the key players, the IRA guerrillas fighting the British rules.