John Mack, professor of psychiatry at Harvard, died after being hit by a car in north London last week. I learnt of the death via an e-mail from the Psychology of the Paranormal Network, an academic group that studies aberrant “anomalistic” phenomena — subjects such as telepathy, ghosts, clairvoyance and alien encounters and abductions.

I was shocked, mainly because I knew the man and liked him, but also because of the banality of his death. Such a bizarre, anguished and exotic life had surely earned a stranger conclusion than an encounter with an alleged drunk in Totteridge.

I met him last year. I had called his office in Boston to arrange a telephone interview, but it turned out he was passing through London and would meet me here. One morning he came round to my flat. He was a very slender, very dark man wearing a flapping raincoat and carrying a large suitcase, both of which seemed to be causing him problems. The permanent expression on his lean, lined face was simultaneously one of distraction and intensity.

He was struck, he said, by the coincidence of my phone call and his visit to London. It seemed significant. We then embarked on a three-hour conversation about the fabric of reality and the way we have deceived ourselves about the true nature of the world. He spoke very slowly and very quietly.

In 1990 Mack had met another acquaintance of mine, Budd Hopkins. Hopkins, a New York artist, had in 1964 seen an unidentified flying object over Cape Cod. He then discovered many people had seen UFOs. In the mid-1970s he also began to come across people who claimed to have encountered and been abducted by aliens.

Using hypnotic regression, he retrieved what appeared to be memories of, among other things, surgery conducted by these aliens on their human victims. Hopkins had become convinced of the reality of these memories and, when he met Mack, he invited him to meet some of the abductees.

Mack met them and also came to believe in their accounts. In 1994 he published a book, Abduction: Human Encounters with Aliens. It caused a media firestorm. A Harvard professor had announced that these tales of alien abduction were true. On Oprah Winfrey and Larry King, Mack said it was all true.

The Harvard authorities were appalled. They attempted to get rid of Mack. But on what grounds? The belief that aliens had visited Earth could hardly be grounds for dismissal. If it were, then 5m Americans were wholly unemployable. That is one estimate of the number who might have suffered alien abduction. If all who had encountered aliens or seen UFOs were regarded as unfit for work, then half the nation — including three or possibly four presidents — could not hold down a job.

And so the university pursued a charge of “therapeutic incompetence”. Mack was, after all, a psychiatrist and it could be deemed irresponsible to encourage patients to believe in alien abduction. But Mack had hired a tough lawyer. Gradually he changed the issue into one of academic freedom.

Mack won and held on to his job — though he was to be marginalised by the university. He pursued his own interests via the John E Mack Institute. The website — www.johnemackinstitute.org — describes its goals.

“Our Research, Clinical, and Educational initiatives examine the nature of reality and experience while providing a safe environment for healing discoveries. Our aim is to apply this emerging knowledge to pressing psychological, spiritual and cultural issues.”

Mack continued to write about his meetings with abductees and also to endure bitter criticism and abuse from full time UFO sceptics like the writer Philip J Klass. At one meeting in Seattle in 1994, soon after the publication of his book, Mack was ambushed by both Klass and a woman named Donna Bassett. Bassett had been one of his abductee patients but, she told the meeting, she had lied.

“I faked it,” she said. “Women have been doing it for centuries.”