MusicBlox: A real-time algorithmic composition system incorporating a distributed interactive genetic algorithm. This paper discusses the motivation, design and construction of a generative music system, `MusicBlox’, (by the author) that utilises a domain specific, knowledge rich Genetic Algorithm (GA). The paper begins by describing the functionality and musical aims of the project, and goes on to detail the implementation of a GA as part of the project’s compositional sub-system, including a discussion of the suitability of using a GA for compositional tasks. The paper concludes that the developed GA is able to produce musically successful results, but that significant additional work still needs to be undertaken before it achieves all the aims outlined