Every weekend, Longform.org shares a collection of great stories from its archive with Slate. For daily picks of new and classic nonfiction, check out Longform.org or follow @longformorg on Twitter. Some siblings are close. Others, not so much. And then there are brothers and sisters like the ones in these six stories, people whose lives are so completely intertwined that it's nearly impossible to think of them as individuals. What happens when the sibling bond is that strong? Incredible works of art. Tremendous professional success. And, at least occasionally, cold-blooded murder. Could Conjoined Twins Share a Mind? Susan Dominus • New York Times Magazine • May 2011 On the shared life of Tatiana and Krista Hogan, four years old and joined at the head:"Twins joined at the head — the medical term is craniopagus — are one in 2.5 million, of which only a fraction survive. The way the girls' brains formed beneath the surface of their fused skulls, however, makes them beyond rare: their neural anatomy is unique, at least in the annals of recorded scientific literature. Their brain images reveal what looks like an attenuated line stretching between the two organs, a piece of anatomy their neurosurgeon, Douglas Cochrane of British Columbia Children's Hospital, has called a thalamic bridge, because he believes it links the thalamus of one girl to the thalamus of her sister. The thalamus is a kind of switchboard, a two-lobed organ that filters most sensory input and has long been thought to be essential in the neural loops that create consciousness. Because the thalamus functions as a relay station, the girls' doctors believe it is entirely possible that the sensory input that one girl receives could somehow cross that bridge into the brain of the other. One girl drinks, another girl feels it."Nightmare on Elm Drive Dominick Dunne • Vanity Fair • October 1990 A comprehensive history of the case against the Menendez brothers:"During the arraignment in the Beverly Hills courthouse, I was struck by the glamour of the young Menendez brothers, whom I was seeing face-to-face for the first time. They entered the courtroom, heads held high, like leading actors in a television series. They walked like colts. Their clothes, if not by Armani himself, were by a designer heavily influenced by Armani, probably purchased in the brief period of their independent affluence, between the murders and their arrest. Their demeanor seemed remarkably lighthearted for people in the kind of trouble they were in, as they smiled dimpled smiles and laughed at the steady stream of Abramson's jocular banter. Their two girlfriends, Jamie Pisarcik and Noelle Terelsky, were in the front row next to Erik's tennis coach, Mark Heffernan. Everyone waved. Maria Menendez, the loyal grandmother, was also in the front row, and aunts and uncles and a probate lawyer were in the same section of the courtroom. Several times the boys turned around and flashed smiles at their pretty girlfriends."Meet the Shaggs Susan Orlean • The New Yorker • September 1999 In the late 60s and early 70s, Austin Wiggins forced his three teenage daughters to play their strange music at New Hampshire ballrooms, firm in the belief that they would become stars. They did not:"The girls liked music -- particularly Herman's Hermits, Ricky Nelson, and Dino, Desi & Billy -- but until Austin foretold their futures they had not planned to become rock stars. They were shy, small-town teen-agers who dreamed of growing up and getting married, having children, maybe becoming secretaries someday. Even now, they don't remember ever having dreamed of fame or of making music. But Austin pushed the girls into a new life. He named them the Shaggs, and told them that they were not going to attend the local high school, because he didn't want them travelling by bus and mixing with outsiders, and, more important, he wanted them to practice their music all day. He enrolled them in a Chicago mail-order outfit called American Home School, but he designed their schedule himself: practice in the morning and afternoon, rehearse songs for him after dinner, and then do calisthenics and jumping jacks and leg lifts or practice for another hour before going to bed. The girls couldn't decide which was worse, the days when he made them do calisthenics or the days when he'd make them practice again before bed. In either case, their days seemed endless. The rehearsals were solemn, and Austin could be cutting. One song in particular, 'Philosophy of the World,' he claimed they never played right, and he would insist on hearing it again and again."Double Vision Lawrence Weschler • VQR • April 2009 On the perspective-bending art of identical twins Trevor and Ryan Oakes:"The way other identical twins might invent a spooky secret language, the two of them became engaged in a long-term conversation, a continuous tandem investigation into the very fundaments of visual perception. 'On long drives,' Trevor recalls, 'we used to talk about the way a bug splattered on the windshield would appear to double if you looked out beyond it, and what then happened when you tilted your head from side to side.' How old were they when they were doing this? 'Oh,' surmises Ryan, 'three or four.' They'd dissect the foreshortening of approaching rows of telephone poles, tapping out rhythms with their fingers in syncopation with the passing poles, and they'd talk about that. They spent a lot of time analyzing their parents' potential sightlines as they hid in a pantry or up on the garage roof behind the basketball backboard. (What for other kids was just hide-and-seek for them proved but one more occasion for investigation into optical geometry.)"The Brothers Emanuel Elisabeth Bumiller • The New York Times • June 1997 How three brothers from Chicago found tremendous success in their respective fields—Rahm in politics, Ari in Hollywood and Zeke in medicine—by their mid-30s:"All are rising stars in three of America's most high-profile and combative professions. All understand and enjoy power, and know how using it behind the scenes can change the way people think, live and die. All have been called obnoxious, arrogant, aggressive, passionate and committed. All three get up before dawn. All are the sons of an Israeli father, now a 70-year-old Chicago pediatrician, who passed secret codes for Menachem Begin's underground. Irgun, and an American Jewish mother, who worked in the civil rights movement and owned, briefly, a Chicago rock-and-roll club. All three also worry about a less successful Emanuel: Shoshana, 23, their adoptive siser, who crash-landed into the family at the age of 8 days, when the brothers were in their teens."Have a favorite piece that we missed? Leave the link in the comments or tweet it to @ longformorg. For more stories, check out Longform.org's complete archive.