He would have never imagined to come across a handwritten book about the Mythic Garden, just like that.
It was not as if he had done anything specific to gain it and one could say that the book was thrown towards him by a lucky coincidence.
Jason thought that it was weird for somebody to have a handwritten book about the Mythic Garden, however, it was even weirder that the owner of this book had died in the gigantic forest's center as if he didn't know about its dangers.
Reading through the first few pages of the book, Jason could immediately tell that the book was the real deal which caused him to become even more suspicious about the dead owner's behavior.