The Journal of Jonas Ravencroft was written by Dr. Jonas Ravencroft, the founder of the Ravencroft Institute in Westchester County. In it, he documented the complete history of the asylum and the land on which it was built from its discovery to his own suicide.
In addition to Dr. Ravencroft's notes, the journal contained detailed anatomical sketches of the various monsters and supernatural entities that Dr. Ravencroft encountered over the forty-six years he was the institute's director.
Mayor Wilson Fisk financed the cleanup of the destroyed asylum. During the cleanup, the journal was discovered amidst the ruins, revealing the long-buried secrets of the facility. It was eventually taken by Misty Knight so Fisk couldn't use it to make things worse for Ravencroft.
The journal was later given to John Jameson, Ravencroft's head of security, which he hid somewhere. When the Unwanted, vampires created at Ravencroft during World War II who had lived hidden beneath the prison for decades, took over the prison, their leader Bud Adams tried to force Jameson to reveal where he hid the journal so he could use its contents to ensure Ravencroft was closed down permanently. However, Jameson eventually admitted that the journal had gone missing. Jameson didn't know that Ravencroft consultant Norman Osborn had taken the journal during a commotion he created so his benefactor, the J.A.N.U.S. organization, could use its contents for their own benefit.