Unlike Dionne Warwick, Etta James does not want to be your psychic friend. And unlike Aretha, she might give you the impression that she doesn’t particularly care for your respect, either. Etta is sort of the dark side of the blues world, a genre that already lives in shadow. She’s known for being suggestive to the point of indecency onstage, which can’t come as a surprise from the girl whose first recorded song in 1955 was titled, for about a minute, “Roll With Me, Henry.” But when you hear “At Last,” the title song of her 1961 debut, why you just can’t believe there could be so much light in the world. Etta James and The Roots Band plays the Landmark Theater Sunday, Oct. 15, at 7 p.m. Tickets are $36.50-$56.50. Call 262-8100 or visit www.ticketmaster.com.