(Image Credit: Markus Schreiber/AP Photo)

It was supposed to be their final meeting. Liliesleaf Farm was the secret command post for the men planning to overthrow South Africa's apartheid government. None of them knew it would be raided by police in 1963. Many of the men would spend the next two decades in prison.

Nelson Mandela was already there. But Bob Hepple, Mandela's legal adviser, was among those arrested at Liliesleaf 50 years ago Thursday.

His new book, "The Young Man With the Red Tie: A Memoir of Mandela and the Failed Revolution 1960-1963," is out this week.

Hepple, 80, sat down with ABC News' Reena Ninan in South Africa.

Q: Your book has a very catchy title. Can you explain?

A: When I was 19 years old, as a young ANC [African National Congress] activist, I was arrested with 20 or so other whites. We went into a black township to hear a concert. White people weren't allowed without a permit, which we failed to get. They brought us to court. We were charged with illegal squatting. The pro-government newspaper described me as "a young man with a red tie." I was eventually acquitted.

Q: How critical was Liliesleaf for Nelson Mandela?

A: Mandela lived there for a while when he was underground. It was a safe house. He went by the name David Motsamayi. It was a 28-acre estate a few miles north of Johannesburg. It was a secretive place where a lot of rich people lived. After Mandela was convicted and sent to prison, the ANC continued using it as a command center. I continued to help them until the raid in 1963.

Q: What do you remember about the night of the raid where you were arrested?

A: Liliesleaf had a long driveway. We saw a laundry van come. We didn't realize there were police inside. Then the police and their dogs rushed out of the van and arrested us all. They were tipped off. It's still a mystery who told them. They were detaining people without trial and torturing them. The tip may have come from there. I mention some of the theories in my book.

Q: Tell me something about Mandela most people don't know?

A: I met him when he was 34 years old. I was amazed by his ability to keep people calm. His ability to take control was incredible. When I first met him it was at a meeting police wanted to break up. It almost turned into a riot. Mandela jumped on stage and got people to sing protest songs. It prevented them from rioting. It also calmed the police. He never underestimated his enemy. He'd find arguments to persuade people to his point of view. He was a rational person.

Q: Do you worry about the future of South Africa when he dies?

A: I think the greatest achievement of this man and his colleagues is a democratic constitution, as long as we have that and a free press and independent judiciary there's a great future ahead.