Horn Sonata is a four-movement work that explores a wide range of sonic possibilities offered by unconventional playing techniques on the instrument. The movements differ not only in thematic material but above all in their modes of performance, including playing with the mouthpiece alone, tremolo on the mouthpiece without the instrument, pulling out the valves and playing without them, kissing sounds, multiphonics, and other extended techniques. In the reprise of one movement, the previously played exposition is reproduced by playing back a recording of it through the performer’s mobile phone into the mouthpiece and through the bell of the instrument. The final movement, subtitled Striptease, requires the performer to gradually “undress” the instrument during the performance by removing the valves one by one. The work also contains a brief quotation of a Slovene folk song and incorporates elements of musical performance art. Technically demanding, the sonata is primarily intended for performers engaged with contemporary repertoire.