Ancient documents describing the events surrounding the second-most recent time of awakening.
The Gaia Manuscripts (ガイア文書,Gaia Bunsho?, lit. "Gaia Documents") is an object that appears in Sonic Unleashed. These manuscripts are an ancient collection of documents, records and knowledge chronicling the time of awakening that occurred tens of thousands of years before the events of Sonic Unleashed. They were initially stolen by Dr. Eggman in his attempt to awaken Dark Gaia, but they were reclaimed by Sonic and his friends who used them to undo the doctor's work.
The Gaia Manuscripts contains an encyclopedia of knowledge concerning everything connected to the disaster created by the second-most recent time of awakening, such as records of the disaster, info on the Gaia Temples and their locations, the nature and weaknesses of Dark Gaia's Minions, a detailed description of Dark Gaia and its being, and scenarios of what would happen should Dark Gaia succeeded in its mission. These texts are written in an ancient language that so far only Professor Pickle has been able to decipher.
"The abomination grows strong on the negative energies of the world, sleeping within its core for millennia in wait..." - Gaia Manuscripts, 4:11.
"When the beast is complete, its dark arms shall encompass the planet, ushering in the end of times. The world, in death, will fall into a deep sleep in waiting for the time of rebirth to come." - Gaia Manuscripts, 4:28.
"And the world shall be plunged into the dark of night, the dark of destruction."
"Light shall put out darkness to rout."
Some tens of thousands of years prior to Sonic Unleashed, the time of awakening had just occurred accordingly on Earth, where the planet was split into pieces by Dark Gaia and later reassembled and returned to normal by Light Gaia. At some point either during or after this cataclysm, the Gaia Manuscripts were created which chronicled the events and contained the knowledge of this event.
In the present day, the Gaia Manuscripts came into the possession of Professor Pickle, an expert on ancient literature. The Gaia Manuscripts, however, were stolen by Dr. Eggman, shortly before the beginning of Sonic Unleashed, who sought to awaken Dark Gaia prematurely and use its essence to build Eggmanland. With the knowledge within the Gaia Manuscripts, Dr. Eggman devised his Chaos Energy Cannon to awaken Dark Gaia. The Gaia Manuscripts were then stored inside a vault in Eggman's base in Mazuri, where he also kept Professor Pickle captive.
When Professor Pickle was freed by Sonic the Werehog, Tails and Light Gaia (nicknamed Chip) and the group reclaimed the Gaia Manuscripts as they contained information that was needed to restore the planet after Dark Gaia had been awoken. With the Gaia Manuscripts, Professor Pickle formulated a plan of action for Sonic and enlisted him to seek out the Gaia Temples to restore the planet.
The Gaia Manuscripts remained in the care of Professor Pickle afterwards, who continued to research them for additional information, which proved to be a great assist to Sonic, such as providing the location of the Gaia Temples and uncover the way for him and Chip to free people from the influence of Dark Gaia's Minions.