For 10 years, the Bach Society has splendidly presented an eclectic mix of classical and contemporary pieces played on both traditional and innovative instruments. Among the summer doldrums, this series provides an affordable escape from the local cultural desert island. The recently completed four-concert season included works by Vivaldi, Verdi and Bartók, as well as Bach. One concert even highlighted opera arias performed by a splendid coloratura soprano. Having successfully coordinated the program from its start, Christina Jarvis is stepping aside, so next year, a new captain will be at the helm. But the foundation she has laid will allow the notes to continue to flow, providing Tucson with a musical alternative to the mundanity of endless sunshine.