The Metropolitan Museum of Art recently made available a free 308 page pdf version of their book: 'Extravagant Inventions: The Princely Furniture of the Roentgens' - by Wolfram Koeppe
available here: <https://www.metmuseum.org/art/metpublications/Extravagant_Inventions_The_Princely_Furniture_of_the_Roentgens
"During the second half of the 18th century, the German workshop of Abraham and David Roentgen was among Europe's most successful cabinetmaking enterprises. The Roentgens' pieces combined innovative designs with intriguing mechanical devices that revolutionized traditional types of European furniture. An important key to their success was the pairing of the skilled craftsman Abraham with his brashly entrepreneurial son David, whose clients included Louis XVI and Marie Antoinette of France as well as Catherine the Great of Russia. This landmark publication is the first comprehensive survey, in nearly four decades, of the firm from its founding in about 1742 to its closing in the late 1790s.
The Roentgen workshop perfected the practice of adapting prefabricated elements according to the specifications of the customers. Detailed discussions of these extraordinary pieces are complemented by illustrations showing them in their contemporary interiors, design drawings, portraits, and previously unpublished historical documents from the Roentgen estate. This fascinating book provides an essential contribution to the study of European furniture."
For those that would prefer the out of print hard cover edition ($1,481.63): <(Amazon.com product link shortened)>