The innovative, rapidly evolving fields of interactive and generative music present fascinating challenges for musical analysis. Many of these challenges are shared with experimental improvisation and sonic arts; diverse practices with distinct histories that have, to an extent, developed separately from the composition-orientated practices we normally associate with analysis, such as musical notation. To narrow the discussion, this chapter assumes that interactive and generative music is computer-based, whatever mutually informing relationships it enjoys with improvised music and other sound art forms. Music creation that exploits and depends on computers, i.e. computational systems, raises questions about creative methodology, documentation, listener comprehension; in general, the impact of ‘real-time’ computation. The author approaches these issues as a composer and developer of interactive performance systems.