This is quite a nice photo-album of the Art Nouveau movement of the late 19th and early 20th centuries, with primary emphasis on furniture, and a strong secondary emphasis on glass, pottery and other small art-objects. There are also a few photos of Art Nouveau buildings. The color plates are decently reproduced for the time (circa 1973), and I don't recall seeing many of these artifacts in other Art Nouveau photo books. All the works illustrated are European; the author is Italian.
Highlights: a spectacular Dijsselhoff room setting in the Gemeentemuseum, The Hague, and a van de Velde armchair that "suggests the idea of comfort -- without in fact being comfortable."
The book is readily available and inexpensive, and you should consider it if you're an Art Nouveau fan.