Jozef Chominski's writings from the 1950s and 1960s reveal that sonoristics was conceived as a theory that attempted to rationalize the musical language of the mid-century avant-garde and focused on the issues of timbre and texture. One of the most innovative aspects of this theory was the ability to explain the novel sound qualities of twentieth-century music as transformations of traditional musical elements, such as melody or harmony, into 'sonoristic values' - self-sufficient qualities of the musical work of a purely sonic character. This approach allowed for a positive evaluation of many non-traditional compositional means frequently found in twentieth-century music, such as clusters, sound effects generated by conventional instruments (e.g., violin as percussive instrument), or noise acquiring the status of musical material. This article examines a variety of transformational processes, both evolutionary and 'metabolic', that constituted the main objects of sonoristic analyses, and scrutinizes how the concept of transformation informs the analytical language itself. The article further demonstrates how the idea of transformation instigates a methodological shift from 'ideal' structures of tonal music (themes, harmonic progressions, or contrapuntal relationships) to 'real' sound objects given in aural perception. In effect, sonoritics is defined as an analytical theory that replaces the interest in structure deducible from the score with an emphasis on texture as an experiential phenomenon; and transformation is shown to represent the chief methodological paradigm of this theory grounded in the sounding manifestation of a composition.