Selected highlights of the rare book collection of Dr. Robert L. Feller, founder of the group that is now known as the Aging Diagnostics Lab at IPCH (and which began as the National Gallery of Art Fellowship at Mellon Institute in Pittsburgh, PA), are currently on display in a special exhibition at the National Gallery of Art in Washington, DC. Dr. Feller is considered to be a pioneer of conservation science research in the United States. He led the lab in Pittsburgh from its inception in 1950 until 1988, by which time it was known as the Research Center on the Materials of the Artist and Conservator at Carnegie Mellon University. During his tenure as director, Bob published over 100 technical articles and books describing his research into picture varnishes, the effect of light on artifacts and pigments, as well as polymer and paper degradation studies. Some of those papers were co-authored with his wife, Ruth Johnston Feller, a renowned color scientist and pigment chemist. For over 50 years, Bob and Ruth collected rare historical books devoted to their interests in color, paint and textile technology, and art making. This collection of over 2,500 books was recently donated to the library of the National Gallery of Art and this spring, highlights from this donation are on display in a special exhibition at the Gallery, recognizing Bob’s and Ruth’s accomplishments and their devotion to supporting conservation research in these areas.