Last weekend at the 67th Monterey Jazz Festival, the gospel eminence grise Mavis Staples took to the stage of the main area stage, and instantly won the love and support of the 4,000-plus-strong congregation there. Not that this was surprising. The now 85-year-old Staples, the beloved and renowned surviving member of the Staples Singers – led by Pops Staples and hugely popular both in gospel and popular music circles – has long been considered a premiere proponent of gospel and its secular offspring, soul/R&B music.