After practicing Schoenbergian dodecaphony for a short period of time, Alfred Schnittke began to employ the pitch-class aggregate in a free and personal way. In his music, aggregates occur melodically, harmonically, and in a combination of the two, and are often unrelated by traditional row transformations. While Schnittke’s approach to the aggregate changes throughout his oeuvre, three features remain consistent: symmetry, chromatic motions, and diatonic/tertian elements. In addition to an in-depth study of these properties, the uses of interval classes 1, 2, 3, and 5 will be examined in relation to the three features. Moreover, the concept of quasi-aggregates will be studied in relation to complete aggregates. The examples in this article were chosen from analyses of 100 passages taken from 54 works in all genres, spanning over 30 years of Schnittke’s mature oeuvre. Finally, an analysis of the first movement of the Piano Sonata No. 1 will examine aggregates in a broader context.

In twentieth‐century music, not only do SLIDE and Parallel function as transformations between chords, but they also combine triads to form pitch‐class units from which many triadic and non‐triadic subsets are derived. By identifying these subsets, I illustrate the larger frameworks of the SLIDE and Parallel formulae and their unifying roles in the pitch‐class organisation of selected twentieth‐century pieces. After establishing the subset/superset identity, I reveal that the subsets serve two formal purposes, functioning as elements of initiation and closure in relation to the pitch‐class organisation of structural units. Moreover, I show how these subsets/supersets may engage in gradual processes and how they are tied to linear motions and correlative relations. To demonstrate these subsets’ extensive use, I provide examples from pieces written between the 1930s and the 1990s by nine European, North American and Russian composers: Britten, Cabena, Lutosławski, Martinů, Persichetti, Piston, Prokofiev, Schnittke and Shostakovich. I conclude my article by analysing a passage that incorporates all the properties discussed in the article.