A surgical device, comprising: an end effector configured to perform at least one surgical procedure in response to at least one control motion applied thereto from a control unit of a robotic system; and an elongate shaft coupled to said end effector and defining a shaft axis and having an articulation joint configured to facilitate articulation of said end effector in two planes that are substantially perpendicular to the shaft axis upon manipulation of the control unit relative to said elongate shaft such that movement of the control unit is mimicked by said end effector, said elongate shaft defining at least one inner lumen therethrough; wherein said end effector comprises: an elongate channel operably coupled to the elongate shaft and operably supporting a surgical staple cartridge therein; and a pivotally translatable anvil movably supported relative to the elongate channel and configured to move in response to anvil control motions applied thereto between open and closed positions to clamp tissue; wherein the surgical device further comprises: a knife bar operably extending through said inner lumen across the articulation joint, the knife bar having a proximal end rotatably affixed to a knife rack gear that operably interfaces with the control unit of the robotic system, and having a distal end attached to a cutting instrument in the end effector, the knife bar configured to push the cutting instrument through clamped tissue upon axial movement of said knife bar, wherein said elongate shaft is a rotary drive shaft operably interfacing with the control unit of the robotic system and the end effector to apply a rotary control motion thereto upon rotation of said rotary drive shaft; and wherein said elongate shaft further comprises pivotably linked closure tubes (2042,2040) operably interfacing with the control unit of the robotic system and the end effector, the closure tubes configured to apply said anvil control motions when said closure tubes are axially translated along said shaft axis. an end effector configured to perform at least one surgical procedure in response to at least one control motion applied thereto from a control unit of a robotic system; and an elongate shaft coupled to said end effector and defining a shaft axis and having an articulation joint configured to facilitate articulation of said end effector in two planes that are substantially perpendicular to the shaft axis upon manipulation of the control unit relative to said elongate shaft such that movement of the control unit is mimicked by said end effector, said elongate shaft defining at least one inner lumen therethrough; wherein said end effector comprises: an elongate channel operably coupled to the elongate shaft and operably supporting a surgical staple cartridge therein; and a pivotally translatable anvil movably supported relative to the elongate channel and configured to move in response to anvil control motions applied thereto between open and closed positions to clamp tissue; an elongate channel operably coupled to the elongate shaft and operably supporting a surgical staple cartridge therein; and a pivotally translatable anvil movably supported relative to the elongate channel and configured to move in response to anvil control motions applied thereto between open and closed positions to clamp tissue; wherein the surgical device further comprises: a knife bar operably extending through said inner lumen across the articulation joint, the knife bar having a proximal end rotatably affixed to a knife rack gear that operably interfaces with the control unit of the robotic system, and having a distal end attached to a cutting instrument in the end effector, the knife bar configured to push the cutting instrument through clamped tissue upon axial movement of said knife bar, wherein said elongate shaft is a rotary drive shaft operably interfacing with the control unit of the robotic system and the end effector to apply a rotary control motion thereto upon rotation of said rotary drive shaft; and wherein said elongate shaft further comprises pivotably linked closure tubes (2042,2040) operably interfacing with the control unit of the robotic system and the end effector, the closure tubes configured to apply said anvil control motions when said closure tubes are axially translated along said shaft axis. a knife bar operably extending through said inner lumen across the articulation joint, the knife bar having a proximal end rotatably affixed to a knife rack gear that operably interfaces with the control unit of the robotic system, and having a distal end attached to a cutting instrument in the end effector, the knife bar configured to push the cutting instrument through clamped tissue upon axial movement of said knife bar, wherein said elongate shaft is a rotary drive shaft operably interfacing with the control unit of the robotic system and the end effector to apply a rotary control motion thereto upon rotation of said rotary drive shaft; and wherein said elongate shaft further comprises pivotably linked closure tubes (2042,2040) operably interfacing with the control unit of the robotic system and the end effector, the closure tubes configured to apply said anvil control motions when said closure tubes are axially translated along said shaft axis.