Before I learned about this bill, I’d have never guessed that Karrin Allyson had even heard of Nancy King–let alone that she’s adored King’s records for years, as she’s recently said. Though the two share a husky-voiced assertiveness, their territories don’t seem to overlap: King, an intrepid scat improviser based in Portland, Oregon, got her start in 1960s San Francisco; Allyson came of age two decades later in Nebraska and Minnesota, developing a gift for melodic paraphrase and a muscular swing. During the 70s and early 80s, when Allyson might’ve been casting about for models, King made only a couple recordings and rarely toured, focusing instead on raising her three sons; these days she has a pretty low profile outside the Pacific Northwest. Allyson settled in Kansas City in the late 80s, and since then she’s established an international reputation with a series of albums for Concord; the most recent, this year’s From Paris to Rio, accents her inviting timbre, slathering on the romance by evoking Edith Piaf and Antonio Carlos Jobim. King has spent the 90s working mainly with bassist Glen Moore of the group Oregon or pianist Steve Christofferson on duo recordings that celebrate her unpolished sound, forcing it center stage under a bare lightbulb. This joint appearance by King and Allyson, part of Steppenwolf’s “Traffic” series, is their first ever. “Traffic,” founded and until recently programmed by Kahil El’Zabar (he left the series at the start of this season), has sought new insights via the intersection of music and other art forms, like theater, dance, and poetry; here it will contrast generations instead of genres, juxtaposing a style of vocal jazz forged in the tumultuous 60s with one refined in the far more conservative 80s. Even without the novelty of an interdisciplinary collision, this concert promises to be a full evening, stuffed wall-to-wall with inventive, well-wrought, and occasionally daring music. Each singer will perform a full set of her own–King accompanied by Christofferson, Allyson by guitarist Danny Embrey and bassist Bob Bowman–and though they haven’t sorted out the details, they plan to take the stage together before the night ends. Monday, 7:30 PM, Steppenwolf Theatre, 1650 N. Halsted; 312-335-1650. NEIL TESSER

Art accompanying story in printed newspaper (not available in this archive): photos/Patricia Estay/Charles Requien.