Lost Girls promised to be an exciting, unsolved mystery about what happened to 5 young woman near New York city that went missing; it accomplished half of that, it was certainly unsolved but not all that exciting.
The basic set up of the book is divided into three parts. It starts with biographies about each of the 5 girls. Where they grew up, the type of families they had, the struggles they faced in their lives, etc. The second part was about their move to NYC and their lives as prostitutes. The final part was about the mystery of who may have killed them and the putting together facts to better understand what may have happened to lead to their deaths. As it was, all were found in very close proximity to each other in similar ways (except for one girl who went missing after running off in the middle night loudly from a neighborhood. She was the girl who started the whole search that found the other bodies though ironically was found last and not as close to the group).
So, the basic premise as described above was pretty interesting and something that I thought would be a great read. And it was; it started out very well with a superb description about each girl's history and their lives. In fact, by the time they go into prostitution and end up going missing, you really do feel for each of them and their families. The problem with the book is the last third: the search for the girls. As the title makes clear, though the author never blatantly notes it, this is an UNSOLVED mystery. Which in no uncertain terms means there is no real ending. Kolker basically meanders through all the evidence, witnesses, suspects, and tries to juxtapose what might have happened and you are left with ..... nothing. I know little more about who might have done it then I did on page 1. Really there is no good evidence or information about who killed these girls (though one can assume pretty sure it was some guy who found them on Craiglists ads).
Overall, the book is not awful. It's just not great either. It is a mystery but just not a very interesting one. Though the author is pretty good at developing characters and making you connect with them on a general level not having any real sense as to what occurred really made the book suffer. I am sorry if I ruined the ending for you but, as I said there is really no ending anyway, so in many ways I saved you the time from reading the book. Nonetheless, if you are inclined to read it do know that it is a true story with some pretty sad themes running through it and pretty empty ending.