Christoph T. M. Krause lives in Cologne, Germany.

He is a passionate collector of old telephones. The Drum Dial has taken him by storm. Krause loves its design, colours, compact workmanship in its interior and most of all, its unusual way of dialling.

Almost all telephones of the 1950s are equipped with rotary dials, but Siemens broke new grounds with the Drum Dial.

In this second volume, Krause presents the chronology of newly discovered patents, which, since 1931 and with interruptions due to World War II, were developed over two decades, resulting in an innovative total work of art, a "telephone" that is one of a kind.