It's impossible to talk about Standard Operating Procedure without referencing Taxi to the Dark Side. Fortunately, both documentaries are vital to any discussion about US military interrogation techniques. While Alex Gibney's Oscar winner uses the death of an Iraqi taxi driver as a framing device, director Errol Morris and writer Philip Gourevitch (We Wish to Inform You that Tomorrow We Will Be Killed with Our Families) examine the issue through visual evidence (they also collaborated on a book of the same name). While Gibney concentrates on Bhagram, Morris focuses on Abu Ghraib, but his self-described "non-fiction horror film," which features a dramatic Danny Elfman score and slow motion re-enactments, runs along two tracks. First, he aims to find out what happened at the infamous institution. Along with the photographs and video footage, he speaks to the guards and the brigadier general who oversaw their operations, including former army specialist Lynndie England, who has all the charm of Aileen Wuornos (so memorably immortalized in Monster). As in his Thin Blue Line, accounts contradict other accounts. In Morris's world, absolute truth doesn't exist-- it's up to viewers to decide which subjects seem most reliable. This leads to his parallel goal, which is to question the reliability of imagery. Photography was prohibited at Abu Ghraib, so he identifies the responsible parties, the reasoning behind their rule-breaking, and the stories behind the most incendiary pictures. If less emotionally engaging than Gibney's feature, Standard Operating Procedure is just as essential--and every bit as disturbing. --Kathleen C. Fennessy