Background on the application of the neutron activation process, originated by Heather Lechtman and Edward V. Sayre, to the investigation of the Rembrandt paintings at the Metropolitan Museum in New York. Conservator John Brealey suggested the investigation of a painting offered to the museum that he recognized as not by Rembrandt and a certain Rembrandt as reference. The project was carried out by Pieter Meyers and Edward Sayre of Brookhaven National Laboratory. A 19th century French painting was shown to be present under the questioned Rembrandt. See 18-1415. -- AATA