Douze Études by Jacques Delécluse (born 1933) is a set of twelves studies often used as solos for exams or auditions. Written for intermediate to advanced level, they are considered quite difficult, the difficulty progressing throughout the book. 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 thatholds his name and is also the author of a series of seven books 'A la maniere de' for Drums and Piano.