Abstract: A hand controller (10) is provided with which an operator can simultaneously control several degrees of freedom of a mechanism, for example a slave arm (18), single handedly. An operator's handle (12) is connected by four links serially arranged between the handle and elements (50, 48, 46, 42) to a platform (32), these links permitting rotation about three axes (A, B, C) and linear displacement towards and away from the platform (axis Z). The platform is connected by three parallel non-telescopic legs (34) to a base (30) so that the platform (32) (and so the handle 12) can be moved in directions (X and Y) perpendicular to the Z axis. Force and torque feedback may be provided to all motions of the hand controller (10).