How this situation arose the present volume graphically sets forth, as well as the reasons interest in the case has persisted to the present day, exciting a continuing stream of books and articles by both lawyers and laymen.
I would like to ask whether there would not be a preposition between "reasons" and "interest". If I understand the sentence properly, it say that the book describes in a vivid detail how the situation arose and as well as it describes the reasons for/of interest that people still have in the case. I do not know what preposition to choice but "reasons interest" seems to be odd to me. "Interest reasons" is probably nonsense so I am really confused.