Oval, ebonized footstool, circa 1870. Made in England. San Francisco’s Antique & Art Exchange was founded in 1995 by Keith Dieterich and Howard Settle, who buy what they love--and love to mix it up. The resulting mélange, a spectacular collection of furniture, accessories, and classic and hard-to-find items spanning 3,000 years, lures a loyal clientele that includes heads of state, billionaires, artists, haute-couture legends, nobility, and of course, interior designers. Fans of great mirrors, comfortable chairs, and miles of books, they curated this sale with the spirit of an English country house in mind.