Maria-Christina Sayn-Wittgenstein Nottebohm (also known as 'Puppa') is a private art dealer and agent specialising in European paintings and drawings from the 17th to the early 20th century. She was brought up in Europe and her parents took her to museums and churches from an early age. ?She has lived in New York her entire adult life, working in the art world. She now divides her time between Mexico City, Telluride, CO, New York and Europe. She has had the privilege of seeing masterpieces in museums and private collections all over the world. Many years of dealing and thinking about art gives her a unique view point. Her blog, Old Masters Rock is an art newsletter for children aged 7-12.

Gary Tinterow has been Director of The Museum of Fine Arts, Houston since January 2012. Previously he served as Engelhard Chairman of the Department of Nineteenth-Century, Modern and Contemporary Art at New York's Metropolitan Museum of Art. He was curator of European paintings at the Metropolitan Museum of Art for twenty years, before becoming curator in charge of the newly formed department of Nineteenth-Century, Modern and Contemporary Art in 2004 and chairman of that department in 2008.