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Albert Einstein's preserved brain has crossed the Atlantic for the first time. It's a journey that one of the 20th century's greatest minds never intended.

Before Einstein died 57 years ago, he wrote in his will that he wanted to be cremated, his ashes discarded secretly to avoid creating a shrine. But in the early hours of April 18, 1955, after the man who invented modern physics died of a burst aortic aneurysm, the pathologist on call that evening did something very different.

Dr. Thomas Harvey did not have permission to conduct an autopsy, nor did he have permission to keep the brain for himself. But that's exactly what he did - for four decades.  "Knowing that his brain was of interest to most everybody, I saved it and carefully preserved it," Harvey told ABC News in 1996.

Harvey kept the most famous brain in the world after receiving a tentative - and retroactive - acceptance from Hans Albert, Einstein's son, so long as the brain would be used for scientific purposes. But Harvey was no brain specialist and had no ability, at least on his own, to make sure that his prized possession was studied for science. And he clearly had more than science in mind.

He removed Einstein's eyeballs and gave them to Einstein's eye doctor, Henry Adams. To this day, they remain in a safe deposit box in New York City. As Brian Burrell wrote in his book, "Postcards from the Brain Museum," "Why [Harvey] kept it will never be known for certain, but it can be inferred from comments made to various reporters that Harvey was inspired by Oskar Vogt's study of Lenin's brain, and he had the vague idea that cytoarchitectonics might shed some light on Einstein's case [looking for physical proof for why Einstein was so smart]. A simpler and more appealing explanation is that [Harvey] got caught up in the moment and was transfixed in the presence of greatness. What he quickly discovered was that he had bitten off more than he could chew."

Harvey had a technician cut the brain into more than 200 pieces. Many were saved properly, but others ended up in jars in his basement. Then when he moved to the Midwest, they sat in a cider box stashed under a beer cooler. Then, when he wanted to meet Einstein's granddaughter, he put the jars in the back of a reporter's Buick Skylark.

They traveled with him as he lost his medical license, moved to a half dozen states, and finally returned to Princeton, where the story began - only to give the brain to the pathologist who took the job he held that night in 1955. Again and again, Harvey promised to have the brain examined. But it never happened, at least not properly.

"Whenever [reporters] asked what was being done, Harvey would confidently proclaim that he was just one year away from publishing his results," Burrell writes. "He would continue to give the same answer for the next forty years."

Tomorrow, two of the pieces that Harvey saved properly will go on display to the public in London's Wellcome Collection museum, the first time they will have visited London. Brain matter is not much to look at, even Einstein's. Kind of looks like a Rorschach test, to be honest. Black and brownish grey, it's a blob that looks like a cross between someone's head and neck and an oceanic plant.

But nevertheless, Dr. Marius Kwint, the guest curator of the "The Mind as Matter" exhibit, is confident of its value. He does not intend to sweep the controversial nature of how the brain arrived here under the rug.

In fact, that's the whole point. At a basic level, the exhibit is designed, he said in an interview, to give people an idea of what the brain looks like as neuroscience is advancing rapidly. But the exhibit highlights the controversial nature of brain "science."

For years, scientists classified brains in an attempt to prove stereotypes: whether social or based on class or race. If the brain belonged to a murderer, for example, scientists tried to see murderous patterns. Or they tried to prove that black brains were somehow physically inferior to white brains. The science helped reinforce "and create prejudice," Kwint said.

And so Dr. Harvey's claims to dedicate his life to examining Einstein's brain - and then failure to do so before he died in 2007 - fit right in.

"You have to show problematic areas of history in order to cultivate proper respect in the present. You have to represent, show the evidence of historical problems in order to create a resolution of those problems," Kwint says.

And although Kwint does not claim to want viewers to take a moralistic lesson from his exhibit, he suggests a larger point: we need to consider whether we humans are much, much more than the product of what the physical brain is capable of producing.

"The idea that you can detect human variation within a vary mercurial structure of the body sometimes involves dubious practices," Kwint says, "and therefore we should be very skeptical about claims that the most important thing in human identity is the body and what it's made of."

And while Einstein would probably be furious that his brain ended up on a slide in a case in London, he would agree with Kwint's point. He once said that a human being "experiences himself, his thoughts and feelings as… a kind of optical delusion of his consciousness.  This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us.  Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty."

Or, as a sing in his Princeton office proclaimed: "Not everything that counts can be counted, and not everything that can be counted counts."