The common mistake of judging a book by its cover obviously applies to music, and today’s program serves as a reminder of this. More specifically, these three works from the 20th-century are best understood if the listener sheds the possibly deceiving terpsichorean facade of each.

That is not to say that the composers arbitrarily used the word “dance” (whether spelled the German way “Tanz” or the French way “Danse”) in the title of two of the works and the “ballet” designation of the third. Although ultimately the music may not correspond to dance in a conventional way, dance is at least always symbolically present.

Nonetheless, these works solidly derive from conventional European notions of melody and motivic development, notwithstanding an abundance of strident dissonances, complex compound rhythms, and irregular phrases and meter. In fact, many of the melodies presented in these works are easily singable, if not altogether catchy.

Especially knowing that organist and composer Anton Heiller (1923-1979) often used elements of Austrian dance and Bach in his music, might lead an overly inquisitive listener in the wrong direction. In one forceful and definitive commentary about Tanz-Toccata, Heiller himself assured us that nothing in it borrows directly from traditional dances of his homeland, despite the unpredictable shifting of meters throughout the work, which is what Austrian Zwiefacher dances typically do. There is also nothing particularly borrowed from Bach, other than the often-employed toccata genre, not to mention Heiller’s aping Bach’s habit of writing “S.D.G.” (or “soli deo gloria”) at the bottom of the final double bar – although this is a Protestant epigraph, and Heiller’s music is otherwise steeped in Catholicism.

There are also no 12-tone rows to find, despite Heiller’s ardent interest in such things and a score that uses at least a few prominent 12-tone notational conventions of the 1970s, when the piece was composed. Because Tanz-Toccata is dedicated to Heiller’s student, the Swiss organist Monika Henking, writers also often erroneously report that it was written for a festival of dance music that Henking organized – something Heiller again denies.

As a piece of purely abstract music, the overall form of Tanz-Toccata commences with a stark introduction followed by three distinct melodic sections all employing similar short motives. The introduction then recurs, moving to a different “key,” and the three melodic sections return roughly the same way (intro-A-B-C-intro-A’-B’-C’), although the first melody is substantially altered the second time.

In the introduction, an opening ascending three-note figure which leads into an E-major triad portends a study in stepwise motion with some tonal reference, although this is followed by a repetitive pulse pattern suggesting a very deliberately contrasting idea. Heiller develops these two contrasting materials throughout the work, arranged metrically in time signatures and groupings of two, three, five, and seven beats.

Heiller also borrows Messiaen’s rhythmic technique of valeur ajoutée (additive value or added rhythm) derived from a Hindu rhythmic practice of inserting an extra shortened beat into an otherwise regular pulse (for example, a bar with the time signature of 5/16 inserted into a group of 3/8 bars, adding an extra 16th note into an otherwise steady 8th note pulse). Another technique of stacking parallel statements of one motive may suggest canon or fugue, but ultimately is nothing more than repeating the same idea several times, each time adding another layer of thick harmony.

Registrations for the pipe organ are also carefully written into the score. Most notably, the use of vox humana for some of the melodies reminds us that these melodies are conceived to be sung.