Douze Études particularly helps to develop precision and mastery over the roll. It uses dynamic changes, placement of ornaments and frequent time changes. It is a must for serious percussionists and, as such, is widely used all over the world. The author, Jacques Delécluse , is a soloist at the Paris Orchestra and a professor at the Conservatoire National de Musique de Paris. He has conceived a keyboard-percussion instrument that holds his name and is also the author of a series of seven books “À la manière de” for Drums and Piano.