Everything inside Donald Trump's 'Black Book' that could mean the end of the world if opened

Everywhere the US president goes, the 'nuclear football' must follow so that America's capacity to launch nuclear weapons isn't hamstrung by their commander in chief being away from the important buttons.

While the name suggests it's some kind of ball that you'd really not want to be throwing around, it's actually a reinforced briefcase with the official name of the Presidential Emergency Satchel.

It was initially nicknamed the 'satchel' or 'black bag', but it got its far more famous nickname around the time of the JFK presidency because of the way it would be passed between aides and someone would need to be carrying it at all times.

Remember, these are Americans and they think a football is something you hold in your hands.

Among the contents of the nuclear football is the 'Black Book', one of the most important documents in the world which must always be kept near the US president who at time of writing is Donald Trump.

Where the president goes, the nuclear football follows (BRYAN DOZIER/Middle East Images/AFP via Getty Images)

What is the 'Black Book'?

According to Time, the 'Black Book' is a 'cryptic set of documents' which has been 'parsed down from a much larger operational plan for nuclear war'.

Nuclear weapons engineer Dr Glen McDuff explained that this mysterious document gained its nickname for a particularly grim reason.

"It’s called the Black Book because it involves so much death," he explained, and since it's part of the nuclear football kit it goes wherever the president goes.

Writing in his book Breaking Cover, former White House Military Office director Bill Gulley described it thus: "The Black Book was about 9 by 12 inches and had 75 loose-leaf pages printed in black and red."

Sounds serious.

The 'nuclear football' appears to have a little antenna coming out of it (BRENDAN SMIALOWSKI/AFP via Getty Images)

What information is in the book?

Each component of the nuclear football forms a different part of the US nuclear response, though despite what you might think there isn't a big button Trump can press to launch nukes from wherever he is.

The Black Book contains the nuclear launch options in the event that the president decides the US needs to trigger a nuclear war.

Within the pages of the Black Book are plans which list which targets could be struck, what weapons delivery systems would be used and the timings that would be required.

So if Donald Trump decided he wanted to launch nukes he'd be able to look through the Black Book pages to see what the US had planned to hit, what they'd planned to hit it with and when they could hit it.

There are other nuclear footballs with identical Black Books, meaning that in the event of nuclear war the president would be looking at the same plans as the people they were speaking to.

Given the damage a nuclear war would do to the world, the plans contained within would be catastrophic doomsday scenarios.

The Black Book contains plans for how the US would use nuclear weapons (Alex Wong/Getty Images)

What else is kept with it?

The other components of the nuclear football are kept alongside the Black Book.

Along with the book is a folder which contains information on the US emergency broadcast system, another book with listings of classified sites and something known as 'The Biscuit'.

It's not for eating in case Trump gets hungry during a nuclear catastrophe.

It's a small card containing the president's authentication codes which would be read aloud to confirm their identity, so not just anyone could start a nuclear war.