Abstract: A vibration-isolating apparatus having orthogonal X, Y, and Z axes is provided for mounting a payload to a base. The payload contains a torque producing device. Torque generated about the X-axis in the payload is communicated to the base through a stiff linkage in the rotational degree of freedom about the X-axis. The apparatus includes first and second support frames, the payload mounted on the first support frame and the second support frame mounted to the base. Gimbal means permit rotation of the payload about the Y and Z axes. Linear dampening means dampen forces between the payload and base communicated linearly along the X, Y and Z axes and rotation dampening means dampen forces between the payload and base communicated rotationally about the Y and Z axes.