A method for mounting machinery, and for isolating vibration therefrom, the method comprising the steps of: (a) supporting said machinery by means of a support that includes a plurality of resilient mounts, each mount comprising a passive resilient means for fully supporting the static load of the machinery, and active isolation means; and (b) controlling said active isolation means of each said mount, the step of controlling including the steps of: (i) sensing motion of the support in rigid body modes of motion, the rigid body modes being the three translational modes, surge, sway and heave; and the three rotational modes, roll, pitch and yaw; (ii) filtering, from the sensed motion, displacement arising from excited resonances; (iii) calculating modal restoring forces; and (iv) applying local demand forces to each said resilient mounts for compensating for rigid body modes of motion; the step of controlling said active isolation means being arranged such that: (i) below the mount resonant frequency a performance parameter of each mount is essentially that of the passive resilient means; and (ii) above the mount resonant frequency and over a desired frequency band, essentially a zero stiffness of each mount is maintained to excited structural resonances, and rigid body modes of movement of the support are compensated by applying local demand forces to each said resilient mount. (a) supporting said machinery by means of a support that includes a plurality of resilient mounts, each mount comprising a passive resilient means for fully supporting the static load of the machinery, and active isolation means; and (b) controlling said active isolation means of each said mount, the step of controlling including the steps of: (i) sensing motion of the support in rigid body modes of motion, the rigid body modes being the three translational modes, surge, sway and heave; and the three rotational modes, roll, pitch and yaw; (ii) filtering, from the sensed motion, displacement arising from excited resonances; (iii) calculating modal restoring forces; and (iv) applying local demand forces to each said resilient mounts for compensating for rigid body modes of motion; the step of controlling said active isolation means being arranged such that: (i) below the mount resonant frequency a performance parameter of each mount is essentially that of the passive resilient means; and (ii) above the mount resonant frequency and over a desired frequency band, essentially a zero stiffness of each mount is maintained to excited structural resonances, and rigid body modes of movement of the support are compensated by applying local demand forces to each said resilient mount. (i) sensing motion of the support in rigid body modes of motion, the rigid body modes being the three translational modes, surge, sway and heave; and the three rotational modes, roll, pitch and yaw; (ii) filtering, from the sensed motion, displacement arising from excited resonances; (iii) calculating modal restoring forces; and (iv) applying local demand forces to each said resilient mounts for compensating for rigid body modes of motion; (i) below the mount resonant frequency a performance parameter of each mount is essentially that of the passive resilient means; and (ii) above the mount resonant frequency and over a desired frequency band, essentially a zero stiffness of each mount is maintained to excited structural resonances, and rigid body modes of movement of the support are compensated by applying local demand forces to each said resilient mount.