Handcuffed and with a hood over his head, Adam Gamal could hear the sound of explosions around him. 

At just 5ft tall, he was at the mercy of a bearded interrogator almost twice his size. 

The giant hit him so many times he thought he was going to die.

He was bombarded with questions and other Americans around him were begging for the torment to stop.

But he wasn’t in a war zone and the blast sounds were only simulations.

Gamal was at the beginning of the brutal process of being selected for the most secretive fighting force in the U.S. military. It’s so classified, it doesn’t even have an official name.

Adam Gamal, with his face obscured to protect his identity, was part of an elite U.S. special operations team so secret it didn’t have a name

He spent three weeks getting constantly smacked during interrogations, walking miles in deserts and training until he was so exhausted he couldn’t move.

It was all part of the hellish program to qualify for a unit of intelligence operatives who track down the biggest threats to the United States – while operating almost completely in the shadows. 

He found terrorists so he could pass on coordinates for missile strikes and gathered information on targets who had evaded American forces for years.

The Navy SEALs and Green Berets are well known for some of the most historic and dangerous missions in history.

From the raid that killed Osama Bin Laden to the capture of Panama’s military leader Manuel Noriega, their names are etched in military folklore.

But Gamal’s elite team is so clandestine it is only known unofficially as The Unit or The Activity.

The Department of Veterans Affairs doesn’t keep any records and members can’t ever discuss any details of the work they are involved in.

Adam (right) and his boss prepare to go out on a mission. The location is classified and the details have never been revealed

Adam (left as a boy scout) grew up as a Muslim in Alexandria, Egypt. The smallest student in his class, he gained an understanding of an array of modern cultures thanks to the city’s metropolitan surroundings

After going through hell, Gamal was selected and would embark on deployments to fight U.S. enemies in the most dangerous places on the planet.

Arriving through the doors of a grim East African hospital after getting shot in the stomach, he fully expected he was going to die and never see his wife or daughter again.

He tracked the head of the Somali branch of Al Qaeda and passed his location to the U.S. Navy, so they could take him out with a payload of guided missiles.

Operators serving with him would dress as tourists to follow members of terrorist cells in cities around the world.

When deployed he would be constantly under surveillance, and would come back to his hotel room to find the contents of his suitcase dumped on the floor.

The story of his life – The Unit: My Life Fighting Terrorists as One of America’s Most Secret Military Operatives – is the first inside look at the highly-classified unit and serves as a message to the modern U.S. military

When he asked staff if anyone had been in his room, they simply shrugged their shoulders and looked at him with the same suspicion of those following him.

He has been to the most volatile parts of the Horn of Africa and has tracked down the globe’s most wanted terrorists.

Al Qaeda and the Taliban were among his targets, but only he and those he served with will know the full extent of his sacrifice.

Adam Gamal is a pseudonym because he can’t reveal his real name.

He even uses a voice changer to speak to DailyMail.com from where he lives, which he also cannot tell us.

And despite the fact that his career finished years ago, he is sworn to silence about the full extent of his work.

The story of his life – The Unit: My Life Fighting Terrorists as One of America’s Most Secret Military Operatives – is the first inside look at the highly-classified unit and serves as a message to the modern U.S. military.

The book had to be screened by the Pentagon and approved before publication. Parts of the final version are still redacted. 

Gamal grew up in a Muslim household in Alexandria, Egypt. 

The smallest student in his class, he gained an understanding of an array of modern cultures thanks to the city’s metropolitan surroundings – something that would serve him well when he was on assignment overseas.

But he didn’t yet know that his hours spent running along the sandy beaches was actually preparing him for missions in Bosnia.

He also couldn’t have known that his strict father – who insisted he come home between prayers at the mosque and forbade him from hanging out with certain ‘bad’ influences at school – would protect him from the growing influence of the extremist Islamic factions which sprouted the militants he would later take on in his decorated military career.

While growing up, the Muslim Brotherhood was in local mosques and schools sharing the propaganda and teachings that formed the foundations of the likes of Al Qaeda, Al-Shabab and the Taliban.

His emigration to the United States at the age of 20 was the turning point – even though, ‘fresh off the boat’, he was barely able to speak any English.

The elite team that is so clandestine it doesn’t have an official name – and is only known as The Unit or The Activity

Adam poses with his wife and daughter, he has never been able to share some the details of the sacrifices he made chasing down the world’s most wanted terrorists 

It was his first time out of Egypt and when he touched down in New York, a cop had to show him how to use a subway turnstile.

After a few years sleeping in spare roomsin New Jersey and taking jobs that got him just enough money to buy food, he signed up to the military.

A few years in, he received an invitation to sign up to the secretive unit. 

At the first briefing he was told: ‘We can’t tell you who we are. We can’t tell you what you’ll be doing.’

Those who weren’t interested in the covert position were told to leave.

He was still struggling with his English, and learned with the help of a book he was given by an Irish-American comrade.

None of his deployments were the same.

For four years he hunted Aden Hasii Ayro, the leader of the Somali branch of Al Qaeda.

Every time The Unit found the location of the terrorist trained in Afghanistan, he disappeared.

The advertisement for recruits in the highly-secretive Unit

But in the middle of a May night in 2008, Gamal had eyes on Ayro and coordinated an airstrike with $5million worth of missiles from a US Navy ship off the coast of Africa.

On another assignment, while working in an embassy in an undisclosed location in East Africa, he walked into his office and suddenly heard an explosion.

He was back on duty after being shot in the intestines in an ambush on the way back from dinner.

His daughter was three years old and his wife, still in her twenties and unaware of most of the work he was doing, was too young to be a widow.

If he died ‘she would be p***ed,’ he thought. ‘I think out of the fear of my wife, I didn’t die,’ he said.

After weeks in hospital and still taking painkillers, he returned to work and was back in the firing line.

The blast outside the embassy made him shout to the staff crawling under the desks around him: ‘This is not a f***ing drill’.

He heard a second explosion, and needed to get American diplomats out and away from the neighborhood that had five or six embassies.

Terrorists had two vehicles outside, including one filled with propane tanks.

One of the men grabbed an AK-47 and started firing at random from behind the car. Local security working at the embassy ended up killing the militants and blowing up one of the vehicles when they fired at the propane tank.

Gamal hoped that his wife wasn’t watching the news, seeing an attack on a ‘random-a** embassy’ she didn’t even know he was stationed at.

But, looking back, he recognizes that his upbringing and the color of his skin meant he was an ideal fit for The Unit. 

He could blend into communities under the guise that he was either Arab-American or Hispanic.

It also meant he was stopped at TSA check-in lines for screenings and Marines asking him whether his U.S. passport was stolen.

As America’s military faces a potentially catastrophic recruitment problem, he believes hiring more recruits with an ethnic background could fix it.

‘I wanted to show the American public what special operations do, and how it could benefit from diversity,’ he told DailyMail.com.

‘Most of the books on special operations are written by, for the lack of a better term, your average white American from the Midwest,’ he added.

‘America is a country of immigrants. Without the strong immigrant community, I think we would be missing out big time.

‘So rather than demeaning immigrants, I think we should embrace them.’

He also says that immigrants who arrive in America thinking they are going to be Uber drivers or pizza delivery guys can have an impact by joining the military.

Gamal also wants better care for veterans. Even in the Special Forces community, those he served alongside have suffered at the hands of PTSD.

Too many, he says, get to the point of no return and take their own lives.

‘I would’ve never gone that far in my life without being in the military,’ he told DailyMail.com. ‘The Unit took me to a different level.’

‘But what I want to leave everybody with is,we are losing a lot of veterans to suicide.

On surveillance missions, operatives in The Unit would pose as tourists to track down members of Al Qaeda 

Adam and members of his team prepare their equipment in their quarters while deployed 

Green Berets of the 3rd Special Forces Group get ready to complete a freefall over North Carolina 

The Bronze Star Adam gave to his daughter for her services when he retired in 2006

‘We are not doing a good job of taking care of our veterans. They don’t just need medical care. They need social care

‘When they leave the military they lose camaraderie they used to have.’

He believes support for the special operations is even more critical. When Americans tell elite soldiers ‘thank you for your service’, many don’t know what they have done.

‘They can’t even talk about what they have done, and we need a platform where we can help them’.

When it comes to what The Unit is doing now, he believes they are ‘everywhere’ and ‘evolving constantly’ as one of the deadliest forces in the world.

And even if he knew where they were and who was involved, he wouldn’t tell us.

The Unit: My Life Fighting Terrorists as One of America’s Most Secret Military Operatives by Adam Gamal and Kelly Kennedy is available online and in most bookstores