Chorus Austin opens its 52nd season with a set of “modern mantras,” composed as rounds by the songwriters of October Project, in the world premiere of The Book of Rounds: 21 Songs of Grace. The concerts, featuring the 32-voice Chorus Austin Chamber Ensemble and Youth Chorus, are at 7:30 p.m. Saturday, Nov. 5, and 4 p.m. Sunday, Nov. 6, at St. Matthew’s Episcopal Church, 8134 Mesa Dr.

“The Book of Rounds is a special piece for many reasons,” said Chorus Austin Artistic Director Ryan Heller. “These 21 ‘modern mantras’ embody the human experience: from longing to loving, from unrest to hope and joy. The atmosphere captured in each individual piece is always powerful and captivating,” he said.

Musically, he noted, “the rounds are at once beautiful, often simple melodies, then taken into arrangements that range from quiet, serene and meditative to complex, sophisticated, rhythmic, driving or soaring.”

The Book of Rounds is a song cycle of 21 original musical rounds by award-winning composer Emil Adler and poet/lyricist Julie Flanders of October Project co-produced with the band’s lead vocalist Marina Belica. The work features vocal arrangements by Keiji Ishiguri and was released last year as a recording on Sounds True Records.

Innovators in the ever-changing music world, Belica, Flanders and Adler have released a succession of highly acclaimed independent recordings following two albums that helped define the musical landscape of the 1990s. They have sold more than a half million records, with headline tours throughout the country and songs featured widely on television, radio and in film.

“Working with October Project is an absolute joy,” Heller said. “Julie, Emil and Marina have been the best of collaborators as we bring The Book of Rounds to life. Their enthusiasm for the piece and for Chorus Austin is contagious; their generous spirits are captured not only in the Book of Rounds, but in every conversation we have.”

The concert also showcases the Chorus Austin Youth Chorus in a new round, “Calling,” composed by Heller with lyrics by Flanders.

Members of October Project will be special guests at the November Chorus Austin concerts.