While Wolfgang Gabriel has composed several important works for bass clarinet with piano, the Sonata Op.72 was his first work for the solo bass clarinet.

The centerpiece of the Sonata is an exquisite set of variations on an original theme which forms the 2nd movement; the linear sense and delicate writing displayed in this movement are simply wonderful. The variation idea is revisited in the 4th movement, a Passacaglia which is another example of this composer's mastery of the variation form. The opening Toccata and virtuosic, clever Scherzo complete the work. The Sonata is unusual in that although the writing is lyrical and expressive throughout, the composer regularly calls for the full span of the extended-range bass clarinet. This dramatic work has a duration of approximately 21 minutes.