Abstract: A method and apparatus for controlling a drilling operation involving the rotation of a bottom-hole assembly carried by a drillstring. In one embodiment, an integrated, closed-loop rigsite analysis system is provided for acquiring and analyzing real-time mud logging and downhole data, and displaying in real-time values of one or more operator-controllable parameters, along with dynamic critical values of at least one controllable operating parameter, thereby enabling an operator to modulate such parameter on a real-time basis to optimize operation. The integrated information is derived by intelligent combination of data into meaningful and useable information that can be displayed in an informative manner.