My research focuses on understanding the sensorimotor control of the arm and hand in humans. I am especially interested in object manipulation and tool use. Object manipulation and tool use is an essential feature of human behaviour. It represents a challenge for sensorimotor control because each time an object is grasped, the dynamics of the arm changes. In order to move skillfully after grasping an object, the motor commands to the arm and hand must adapt to the particular dynamics of the grasped object. My research uses virtual reality systems to simulate tasks in which subjects grasp and manipulate virtual objects. The simulation includes computer controlled visual feedback and robotic interfaces which simulate the forces and torques associated with manipulation of the object. Results from experiments elucidate the sensorimotor processes that mediate object manipulation and allow computational models of those processes to be developed.