We present the MusicSurfer, a metadata free system for the interaction with massive collections of music. MusicSurfer automatically extracts descriptions related to instrumentation, rhythm and harmony from music audio signals. Together with efficient similarity metrics, the descriptions allow navigation of multimillion track music collections in a flexible and efficient way without the need for metadata nor human ratings. Categories and Subject Descriptors H.5.5 [Information Interfaces and Presentation]: Sound and Music Computing – signal analysis, synthesis, and processing, systems. General Terms: Algorithms