Where Ancients Dare Not Tread
Forbidden History is a document which began life as the mission report Hunter Jusenkyou filed on his mission into Runarin Space. The document, heavily revised and with many details ommited, was later published by Jason Bur'I as a research paper, and is generally regarded as changing the course of history, in terms of modern scholars understanding of Pre-History.
The document was later turned into a book, and revised several times during the Age of the Dragon. Though Jason is responsible for publication and most of the revision, the book always lists Hunter as the author, and is based on research the two of them conducted together during their time at Gudersnipe School and throughout the rest of their lives.
As with many great discoveries, the book was lost throughout the Long Night, however copies of it survived in the Library of Arindell, and at the start of the New Day it became the basis for the standard historical text.
Though the initial publication happened after Jason's graduation, the Foundation was not overly thrilled by the paper. Including calling into question, and outright overturning, many pieces of established doctrine, the paper came dangerously close to revealing highly classified mission logs. Logs that could, at the very least, strongly challenge the Foundation's position within known space, and, at worst, spark a civil war across the Alliance.
Instructor Ruise is the Foundation's head of Ancient Studies and responsible for overseeing and revising published Foundation doctrine regarding the eras before the Golden Age. Privately, he as admitted to being more upset about the amount of re-writting that has to be done in the wake of the publication, while publically he feels Hunter and Jason revealed information that was best kept secret. In his public comment, he said:
"This is all because a couple of boys went somewhere they shouldn't have gone, saw something the weren't supposed to see, and wrote a book they weren't supposed to write."
Jason named the book after a region of space he then believed to exist, and later visited, where (he believed) the Progenitors began.