The Dutch painter Rembrandt (1606-1669) left behind the largest series of self-portraits in the history of art. These paintings were produced over a period of time from age 22 years until just a few months before Rembrandt's death at age 63. This series gives us a unique opportunity to explore the development, maturity, and aging of the artist. The changes in Rembrandt's face and expression from one self-portrait to the next may be attributable to any combination of the following factors: normal aging changes, modifications and developments of his artistic style, alterations in the way he viewed himself, and changes in the way Rembrandt wanted us to see him. In addition, the modifications may be attributed in part to some illnesses from which the artist may have suffered and/or to a decline in his eyesight that may have influenced both his ability to detect details and his ability to paint. (Contains 4 figures and 1 table.)