As you hold this book in your hands, a Bulgarian song travels in outer space. The song in question is "Izlel e Delyu Haidutin," a traditional Rhodope tune sung by Valya Balkanska. It was put on the Golden Record of Voyager 1 and 2 spacecrafts by Carl Sagan, in 1977, in his attempt to acquaint extraterrestrial civilisations with the Earth's culture. Bulgaria's folk music is incredibly varied and, with its compound metres and irregular times, may sound unusual to Western ears. Some of it, like Valya Balkanska's master opus, is slow and heavy.