I haven´t read that one so I don´t know. But my guess would be that the book is filled with same old "bullshit facts" now anybody can find on MafiaWiki, mixed with author´s assumptions of what happened that day. These kind of books doesn´t present new facts and are not books that will stray away too much from what the general reader wants to read about. They are all mainstream and middle of the road. They have to be, if the author/publishers wants to make any money out of them. They won´t sell otherwise.