Brain Trust (Blythe Stanhope Van Renssaeler) was a fictional character from the first book in the Wild Cards anthology series, appearing in the stories "Witness" by Walter Jon Williams (who created the character) and "Degradation Rites" by Melinda M. Snodgrass (who created the character).
Blythe was the wife of domineering New York Congressman Henry Van Renssaeler. When the Wild Card virus infected her, she gained the power to absorb an exact duplicate of another's mind, to know everything they knew; and the first time she used this power was when she involuntarily absorbed her husband's mind. Suddenly she knew it all; his dirty politics and criminal activities, his affairs, and what he really thought about his wife.
Overwhelmed to the point of withdrawal, she was found and brought to Dr. Tachyon, in hopes that he could help her. He used his telepathy to help stabilize her mind, and the two soon began an affair. She was afraid to go back to Henry, and instead joined the organization that would become known as the Four Aces. Unlike Golden Boy and Black Eagle, Blythe, codenamed "Brain Trust", was a behind the scenes member at first. She was sent around the country to copy the minds of some of the world's greatest scientists, such as Albert Einstein, Jonas Salk, J. Robert Oppenheimer and Wernher von Braun, so that there would be "back-up" copies of all their knowledge. This made it even more difficult for her to maintain her mental balance, so Tachyon began tutoring her in Takisian methods of mental control, when he wasn't romancing her.
Unfortunately, the climate of the United States was growing harsher, and the Four Aces were called before the HUAC Committee, who demanded to know the names of any Aces they had dealt with. When Golden Boy let slip that Brain Trust had also absorbed a copy of Tachyon's memories, which meant she knew all the Wild Carders Tachyon had treated, the Committee eagerly called her to the stand and began to browbeat and interrogate her. The fragile union of minds inside her made it difficult to resist, and she began to break down and name names. Tachyon, aghast, tried to telepathically force her silence, but only succeeded in shattering her remaining mental defenses, causing a complete mental breakdown into a gibbering wreck. Tachyon was deported, and Blythe was placed in a mental institution, where she eventually died of neglect.
After his pardon and return to America in the 1960s, Tachyon founded the Blythe van Renssaeler Memorial Hospital in the heart of New York's Jokertown in honor of Brain Trust. More commonly known as the Jokertown Clinic, it has treated and cared for (if not necessarily cured) thousands of victims of the wild card virus. Fleur van Renssaeler, Blythe's daughter with her estranged husband, grew up to hate both the wild card virus and it's creator, Dr. Tachyon. A supporter of anti-wild card preacher Leo Barnett's bid for presidency, Fleur once tried to seduce Tachyon in order to get information from him. During the brief encounter Tachyon imagined himself with Blythe, while Fleur overcame her hatred of Tachyon by fantasizing about Leo Barnett.