First appearance: X-Men (2nd series) #94
Number of volumes: Fourteen
Known holders: Destiny, Mystique, Shadowcat, Rogue, Xavier, Vargas, Gateway, Sage, Storm, Moira MacTaggart
Chronology
When the precognitive powers of the mutant Irene Adler, later known as Destiny, first developed, she was overwhelmed with visions she could not comprehend. Only thirteen years old when it started, she saw futures that depicted people, places and events she couldn’t imagine if she tried. As a way to make sense of what she was seeing, Irene began to write down everything she could, regardless as to whether it made sense to her or not. In a little over a year, Irene had written thirteen diaries, filled with prophesies depicting future events from the mundane to the catastrophic.
Her mutant power of foresight came with a price, as she found her eyesight was fading, until one day she became completely blind. Soon enough, she met a woman named Raven Darkholme aka Mystique, who would not only become her closest confident but also a romantic partner. Irene shared the existence of her diaries with Raven but knew how dangerous they would be if they fell into the wrong hands. Irene hid the diaries away rather than destroy them, as she knew one day they would be needed to guide future mutants through certain events. [X-Treme X-Men (1st series) #1]
Many years passed and Irene was killed, leaving Mystique as the sole caretaker of the diaries. One day, Shadowcat, a member of the X-Men who had the ability to phase through objects, found herself in Mystique and Destiny’s apartment. Destiny had foreseen this event and had created directions for Shadowcat to follow and eventually find one of the diaries. Curious as to what the 
diary said, Shadowcat read some pages but couldn’t understand what they were talking about. Little did she know that the mentions of “betrayal” and a “gathering of the twelve” were hinting at an event that was about to befall the X-Men. Knowing the diary was important in some way, Shadowcat took it back to the X-Men and informed Rogue of her find. Mystique was still in possession of the other diaries, and she would often refer to them to see if she could make sense of any of the predictions. When Xavier found out about the diaries, he managed to get a hold of four of them, which became a cause of great concern to some of the other X-Men. At some point, Gateway also managed to get a hold of one of the diaries. Whether Destiny herself gave it him is unknown, but he kept it safe in his possession. [X-Men (2nd series) #94, 105, 109, X-Treme X-Men Annual 2001]
Worried as to what a man like Xavier would do with all the knowledge written in the diaries, Storm took a team of X-Men and set out to find the rest for the safety of all concerned. The team located a house in Valencia, Spain that belonged to Destiny and, when they broke in, they discovered the precognitive mutant had been well aware of their mission. Before her death, she had organized for a crate of supplies to be left at the house for the X-Men. Amongst the supplies was one of her diaries, but it was stolen by a man named Vargas before the team could get their hands on it. 
Vargas saw mutants as an evolutionary dead-end and made it his mission to wipe them out. Reading the diary, he discovered what the future had in store for himself and the X-Men and he didn’t like it. Amongst the pages was a set of images depicting himself being killed by Rogue, and so he decided to wipe out the team before this future could come to pass. Knowing what the X-Men were planning before they even did allowed him to get the drop on them, and he killed Psylocke to show everyone he meant business. [X-Treme X-Men (1st series) #1-4]
Whilst grieving over the loss of Psylocke, Bishop was taken aback when his mind slipped into the Dreamtime, a level of consciousness similar to the astral plane. There he met Gateway and saw visions of pages from Destiny’s Diaries. Unable to understand what he saw, he told the rest of his team and tried once again to enter the Dreamtime. Taking Rogue with him, she was able to see the pages of the diary for herself, although she struggled to remember them when she woke up. Afterwards, Gateway gifted the X-Men his volume of the diaries, as he knew the time had come for it to be read. [X-Treme X-Men (1st series) #4, X-Treme X-Men Annual 2001]
One of the events in the diaries was about to come to pass as an alien race led by a warrior named Khan set its sights on invading Earth. Gambit was captured and shackled to an altar, and subsequently used to open a portal that allowed an army to step through. The X-Men naturally stood in their way but, during the chaos, Vargas appeared, looking to take care of Rogue. Showing her his diary, she saw images of Gambit on the altar, as well as Vargas’ death at her hands. Rogue tried to tell Vargas the prophesy would only come true if they let it, but he wouldn’t listen. Instead, he began to fight. Vargas overwhelmed Rogue and he impaled both her and 
Gambit with a sword, after which he walked away, believing it was the end. Rogue miraculously survived by channeling Wolverine’s healing factor she had absorbed years before and set out to get revenge on Vargas. Catching up with him, she bested him in one-on-one combat and was about to stab him when she stopped. Deciding to prove that the books were creating a self-fulfilling prophesy, she threw the sword down and walked away. With Destiny’s predications proving to be fallible, the X-Men gave up looking for the rest of the books. [X-Treme X-Men (1st series) 10-17]
Despite proving that the events depicted in the diaries could be avoided, they still contained a lot of information about the future… possible, probable or otherwise. Whilst the X-Men may have placed the diaries in the back of their minds, other parties were still aware of their significance. In the years that passed, the mutant race was depowered by the Scarlet Witch and, with only a 
relative handful of mutants left alive, the world became a much more deadly place for them. Mister Sinister was one such threat and he learned that the mutant race’s salvation was imminent, so he made it his goal to stop it. Joining forces with the Acolytes, Sinister sent out teams to kill any mutant with knowledge of the future, as well as locate Destiny’s Diaries. Since Shadowcat had been in possession of a diary, Exodus and his Acolytes stormed the X-Men’s mansion to get the location of them from her.
When Exodus read her mind, he discovered her memories had been tampered with, whilst she believed she had the diaries herself, they were blank copies. Knowing the diaries could be dangerous, Shadowcat had hidden them and then asked Emma to lock the knowledge of their location away. Emma managed to unlock the location from Shadowcat’s mind, with Iceman and Cannonball being sent to Flint, Michigan to retrieve them. The two men were in for a fight as the Marauders were hot on their tails and they would stop at nothing to get the diaries. What the 
villainous team didn’t count on was Gambit covertly betraying them, as he blew up the diaries during the battle. Sinister was angry, as he knew the broad outline of what was going to happen, but he needed the times and locations of key moments. Whilst the exact number of diaries Gambit destroyed is unknown, it was another to blind Sinister and the X-Men of upcoming events. [X-Men (2nd series) #201-203]
One diary did surface a few years later when the Chaos King attacked Earth, looking to wipe out the universe. When the Thunderbird god briefly resurrected a number of dead mutants on Muir Island, Moira MacTaggart came into possession of a volume. As she read from it, Moira was taken over by the spirit of Destiny, who helped guide the team to defeating one of the Chaos King’s soldiers. It’s unknown how Destiny managed to place a part of her soul inside the diary, but the volume was seemingly lost once more when the group returned to their graves. [Chaos War: X-Men #1-2]
At some point in the past, the entire catalogue of diaries had been copied either by Destiny herself or some other source. They would fall into the hands of Moira once more, who was revealed to be alive and working behind the scenes to manipulate the course of mutant history. [X-Men (5th series) #20]
Upon her resurrection on Krakoa, Destiny was inundated with more visions of the future. She decided it was time to write the fourteenth volume, the contents of which are a closely guarded secret. [Immortal X-Men #3]
Prophesies
Despite the diaries being talked about a lot, very little of what is in them has been revealed. Many of the events depicted were written in strange languages or simply shown in diagrams. The first time the diaries were shown was in X-Men (2nd series) #94 and only text was shown. Phrases such as “Armageddon looms large when Xavier is betrayed,” “death kills the one who is become death” and lots of references to the number twelve and the letter A. This is an obvious allusion to 
the upcoming Twelve crossover that dealt with Apocalypse trying to ascend to godhood by collecting twelve powerful mutants together. During the crossover, Wolverine was revealed to be alive and working for Apocalypse as his horseman of death.
It wasn’t until X-Treme X-Men (1st series) #4 that we got another view of a prophesy, only this time it came from Bishop’s Dreamtime vision. The page depicted a half-naked Gambit being sacrificed on an altar, which was also repeated later on in the issue when a brief glimpse of the real diary was seen. This exact scene would occur in X-Treme X-Men (1st series) #10, when Gambit was kidnapped by an alien race and placed on the altar to open an extra-dimension portal.
X-Treme X-Men (1st series) #4 contains the words
Fire from the sky,
Steel strides ashore,
All that lives is scoured away,
A land made barren evermore
Two bodies, two minds, one soul, twisted and twisted, the stars its destination and blood its unholy name
What price the dream when the center does not hold? Shall the circle stay unbroken?
From the ashes of despair the rain of renewal
The winter of rebirth brings forth a spring of… desolation
With the images accompanying it, the events of the Sentinel attack of Genosha are depicted here, as well as Xavier’s evil twin Cassandra Nova’s involvement in it.
In the X-Treme X-Men Annual 2001, Rogue ventures into the Dreamtime and views a page of the diary herself. She sees members of the X-Men and superhero community surrounded by a malevolent dark cloud with a sinister grin. Events later on in the issue indicate this is referring to the Shadow King gaining freedom after Psylocke’s death and Rogue’s subsequent fight against him.
X-Treme X-Men (1st series) #10 contains a small prophesy labelled as Extract 117/G3 by Sage, who was studying the diaries. In it the following phrase is accompanied by a picture of a team of X-Men squaring off against Deathbird.
Earth shall be her home, the stars her destination
Mothered by war, her father’s her salvation
The price of Xavier’s dream shall be the ancient aeries’s fall
This prophesy might refer to the alternate timeline depicted in the X-Men: The End comics that were released around the same time this issue was. In it a young girl called Aliyah Bishop was revealed to be the daughter of Deathbird and Bishop. Deathbird briefly took the mantle of Horseman of War during the Twelve crossover, and the rest of the words give a very brief outline of the plot of the series.
The next prediction in X-Treme X-Men (1st series) #15 was more clear-cut, as it simply showed a battle between Rogue and Vargas, with the latter being stabbed with a sword. This was the prophesy that spurned Vargas to wage war on the X-Men, but Rogue proved it false by refusing to kill him when she had the chance in #17.
In Chaos War: X-Men #1, a resurrected Moira managed to get hold of a diary and reveal the plans of the Chaos King. Destiny had shown a way of defeating one of his soldiers, but the pages were written in an unknown language. The language mysteriously became readable to the moment they needed it.
Only a few prophesies have ever been outright revealed, but other characters mention the diaries have depicted events that have come to pass. Moira MacTaggart was revealed to have had all the diaries in her possession but, with her exile from Krakoa, it remains to be seen where they went. The fourteenth volume was placed into Mystique's care, with the order that she must not read it until the time comes. Enigmatic as always for Destiny.