A golf club head formed of multiple materials is disclosed. Those portions of the club head that are subject to high stresses during normal use of the golf club head are formed of a metallic material. Most of the material beyond what is required to maintain structural integrity, however, is removed and replaced with a lightweight material. This freed-up mass that can be redistributed to other, more beneficial locations of the club head. The lightweight material also damps vibrations generated during use of the golf club. This vibration damper may be retained in a state of compression to enhance the vibration damping. One or more weight members may be included to obtain desired center of gravity position, moments of inertia, and other club head attributes. A insert formed of multiple materials and having regions of varying thickness may also be included on a rear surface of the club head.