In 2008 the study of Phonology in Milan Rai, a laboratory of experimental composition of the 1950's and meeting point in Europe, attended by distinguished musicians such as Berio and Maderna, was completely reconstructed inside the Museum of musical instruments at the Castello Sforzesco in Milan. A year later RECALL published a volume dedicated to it, containing historical essays and the catalogue of machines collected in the study. This new English language edition contains an update to previously published essays and three new contributions that provide an interesting reflection on the preservation of electroacoustic music and its instruments.