“A Certain Age” by Beatriz Williams. A jazz age socialite has a scandalous affair with a young aviator (“Der Rosenkavalier”, anyone?). “First Comes Love” by Emily Giffin. Two sisters want to trade places; the married one envies the younger’s freedom, the later, motherhood. “Magic” by Danielle Steel, single gusts at an elegant Paree dinner party are set up for romance. “Tender is the Night” and “If I Didn’t Know Better” by Barbara Freethy. Two new Callahan family stories. “Tall Tail” by Rita Mae Brown. A new cat mystery.