Berlioz's Grand traité d'instrumentation et d'orchestration modernes, first published in 1844 with a second edition in 1855, is a classic textbook which has been widely read for over a century and a half by students, composers, historians and all who are drawn to Berlioz the musician or Berlioz the man. Like Rameau's Traité de l'harmonie it is a remarkable example of a great composer venturing into the world of technical and theoretical exposition and producing a masterpiece which affected the musical thinking of generations. In the nineteenth century Berlioz's Treatise (as we shall hereafter call it) was read as a book of instruction; in the twentieth century it became a source book for anyone curious to learn more about the history of instruments and orchestral practice and a revealing exposure of Berlioz's musical thinking. His purpose in writing it was to guide composers towards a more expert and expressive use of instruments and to advise them of pitfalls that the unwary may encounter. This is explained in the book's introduction and again alluded to in the section on ‘Other percussion instruments’: