Opinion Ciatti Ptolomeo wall hung bookshelf. The “column of knowledge” by Opinion Ciatti is 210 cm high and is made of sheet steel, in black. To be mounted on the wall vertically, this is a fabulous way to display books as the thin metal shelving virtually disappears leaving the impression the books are simply stacked. Space saving and stylish way to house your collection. Bruno Rainaldi received the “Compasso d’Oro 2004” for his design of the Ptolomeo collection. The “invisible” bookshelf by Opinion Ciatti has been often copied, but the original is unmatched in quality and manufacture. Three available. Recommended retail price c$2100 each.