Saxophonist Ingrid Laubrock has established herself as an adventurous, innovative, and expressive musician and a compelling improviser. However, on her ambitious recent release, Purposing the Air, it’s not her saxophone that is heard, but her composer’s pen, which takes as its subject the poetry of Erica Hunt, specifically “Mood Librarian—a poem in koan,” from Jump the Clock. Together, the pens of Laubrock and Hunt create an evocative atmosphere as challenging as it is inviting.