As the title of this album suggests, An Arc of Quartets gives listeners unique access to a continuum of composer Michael G. Cunningham's intricate and inviting string music. Five international string ensembles present the album's seven compositions, including Sirius Quartet, the Moravian Quartet, the Millennium Quartet, the Pedroia Quartet and New England String Quartet. These groups' performances of Cunningham's work present the hallmarks of his style of string writing, which is defined by a focus on rhythm, melody, and texture, as well as his gentle yet often dissonant, harmonic language. Although these quartets contain a wide range of sounds and styles, Cunningham maintains a reliable attraction to tense, lyrical melodies, and energetic rhythms. One specific string effect that pervades these works is the glissando, or slide sound, that is produced easily on string instruments. In the middle of String Quartet No. 3, we can hear glissandi spangle an all-pizzicato section, while in the "Zestful" movement of String Quartet No. 5, these sliding gestures are decorated with a trill. This piece's marriage of Cunningham's typical style with uncontrollable, rhythmic energy marks it as one of the more abstract works on the album. Cunningham's quartets utilize special sounds as accents to a core of intriguing textures, evocative melodies, and momentum-building rhythms, all of which remain compelling throughout the album. The composer's impressive skill at creating musical lines is displayed particularly strong in the "Song and Fantasia" movement of his String Quartet No. 1, a piece defined by both soulful lyricism and intense contrapuntal motion.