Lexikon-Sonate is an interactive realtime composition environment for musical composition and live performances - a work-in-progress that was started in 1992. Instead of being a composition in which the structure is fixed by notation, it manifests itself as a computer program that composes musical structures in real time. It takes advantage of composition algorithms that has been developed by Karlheinz Essl since the 1985 years. With this algorithmic music generator on can easily create fascinating and complex musical structures on the fly. Registered users can store them as MIDI files and process them afterwards with sequencers resp. notation programs.

Lexikon-Sonate can be used as an algorithmic music generator for creating fascinating and complex musical structures on the fly. Registered users can store them as MIDI files and process them afterwards with sequencers resp. notation programs.

Furthermore, Lexikon-Sonate is an infinite music installation that can run on a computer for years without repeating itself.

Finally, Lexikon-Sonate can be used as an instrument for live performance of electronic music.

10 years after the Lexikon-Sonate project has started, it has no been re-released as a software environment which - for the first time - offers the possibility to record the output to disk as a MIDI file. This allows registered user of the program to create customized musical structures which can be for compositional (or mere recreational) purposes.