OpenMusic (OM) is a full visual programming language based on CommonLisp / CLOS. OM is icon oriented, uses extensively drag and drop, and has built-in visual control structures that interface with Lisp ones, such as loop. Above the OpenMusic kernel, live the OpenMusic Projects. A project is a specialized set of classes and methods directly written in Lisp, accessible and visualisable in the OM environment. OM may be used as a general purpose functional/object/visual programming language. At a more specialized level, a set of provided classes and libraries make it a very convenient environment for music composition.Objects are symbolized by icons that may be dragged and dropped all around. Most operations are then performed by dragging an icon from a particular place and dropping it to an other place. A lot of classes implementing musical data / behaviour are provided. They are associated with graphical editors and may be extended by the user to meet specifical needs. Different representations of a musical process are handled, among which common notation, sound signal, midi piano-roll. High level in-time organisation of the music material is proposed through the maquette concept.Requirements: