Harold Pinter’s 1978 play enlivens the old story of a young wife having an affair with her husband’s best friend by telling it backward, setting each scene earlier in time than the one before–a device that allows full hindsight into the waning of the illicit couple’s ardor. Bob Bills Productions gives Betrayal a tidy staging under Bills’s direction. Brad Walker and Kelli Cousins as the adulterers make effective use of the script’s enigmatic silences to suggest the lovers’ fundamental lack of communication. But since these lovers, like most, are absorbed in each other, audience members may respond more readily to the excluded husband, played by Jeffrey Baumgartner with a repressed vigor that’s far more intriguing than the stillness born of hot blood grown cold. Through 6/26: Thu 7:30 PM, Fri-Sat 8 PM, Sun 3 PM. Athenaeum Theatre, first-floor studio theater, 2936 N. Southport, 312-902-1500. $19-$24; $15 5/27-5/29.