Clusterin is a multifunctional protein which was independently discovered by more than ten different research groups in the 1980s. New roles of clusterin in brain functions have come to llight which are summarized here by the researchers involved. Recent discoveries include a unique lipoprotein particle containing clusterin and apoE secreted by astrocytes, and the ability of clusterin to promote neurotoxic activities of the amyloid beta peptide, but also to be neuroprotective. Also included is recent information about clusterin and Alzheimer's disease. In all, this is a comprehensive and up-to-date review of clusterin in the brain.