The third in a series of light novels translated from its original Japanese language; Boogiepop at dawn doesn't disappoint it's fans. The book brings us the origins of some of the series main characters, shedding some light on why thy are the way they are. It also adds some depth to them. In particular Kirima Nagi. Some of what was missing from the previous books was just what was motivating these characters to risk their lives fighting these monsters. Who would do such a thing and why? So yes, finally some light is shed. But not too much and only ends with more questions.
Saying that, if you decided you wanted to get into the series now, You'd be confused beyond belief. Maybe they add a list of chronoogical events as they happened. As it happens, the ending sets up the story for the fifth book. Seeing as how this is the third book, I wonder what happens in the fourth?