Mozart wrote Idomeneo when he was twenty-four years old, and the opera was described by Albert Einstein as ‘one of those works that even a genius like Mozart could write only once in his life’. It is one of most astonishing achievements of an altogether astonishing career. In this newly commissioned guide, Julian Rushton explains the special nature of the music in a detailed analysis of its themes and development, while Nicholas Till places the opera in its context as an expression of the Enlightenment. Gary Kahn explores the performance history of an opera which, although largely ignored for over a hundred and fifty years, has now taken its place as part of the international operatic repertoire. A selection of the unique letters between Mozart and his father written during the opera’s composition is also included.