Don't forget to mention this book: Vita di corte in Casa Savoia, written by HRH Princess Maria Gabriella di Savoia and Stefano Papi.
This is a very, very good book if you like to know more about the court life in the reign of the kings Umberto I, Victor Emmanuel III and Umberto II.
Recently, I bought this book and I am very positive about it, although I don't read Italian! There are a lot of photos in it, black and white and also in colour. The chapters are about the three queens in this period: Queen Margherita, Queen Elena and Queen Marie José. There are photos in it of palace interiors, menu cards, music programmes, rare photos of the Queens, photos of court dresses and photos of the wedding of Princess Marie José and Prince Umberto. A very interesting book!