Synopsis (From GoodReads):
The adventures that began with Miss Peregrine’s Home for Peculiar Children and continued with Hollow City comes to a thrilling conclusion with Library of Souls.
As the story opens, sixteen-year-old Jacob discovers a powerful new ability, and soon he’s diving through history to rescue his peculiar companions from a heavily guarded fortress. Accompanying Jacob on his journey are Emma Bloom, a girl with fire at her fingertips, and Addison MacHenry, a dog with a nose for sniffing out lost children.
They’ll travel from modern-day London to the labyrinthine alleys of Devil’s Acre, the most wretched slum in all of Victorian England. It’s a place where the fate of peculiar children everywhere will be decided once and for all. 
Like its predecessors, Library of Souls blends thrilling fantasy with never-before-published vintage photography.

Review:
From the first book in this series (Miss Peregrine's Home for Peculiar Children) I have been fascinated by author Ransom Riggs' one of a kind story-telling.  Using unusual vintage photographs, he has crafted a strange and wonderful tale of "Peculiar" children.  These are children (and adults) who have unusual abilities such as making flames shoot out from their fingertips, animating objects, flying, or having super strength.  Of course, this is meant to represent that everyone has hidden talents.  Often, these talents are seen as liabilities or as downright strange.  People can (and have) been persecuted for their "otherness", and the children in this book are outcasts who have formed their own society.  Under the guidance of a motherly person called a Ymbryne (pronounced imm-brinn), the children live in a time loop where they will be safe and will never age.


In this book, the children must race to save Miss Peregrine as she is held captive by the power-hungry Caul.  Caul has captured many of the ymbrynes and peculiars and seeks to use them to find the legendary Library of Souls.  If he succeeds, all of peculiardom will be at Cual's mercy.

Most of the story takes place in a slum in Victorian London known as Devil's Acre.  This was a real place where the poorest of the poor lived and barely survived.  Ransom Riggs vivid descriptions of this hell-hole was a highlight for me.  That may sound strange but I appreciated that he didn't sugar-coat how awful it must have been.  I have a tendency to romanticize long-ago eras and it was refreshing to be reminded that the good old days were not so good for everyone.

I also was touched by how Jacob came to have empathy for the monstrous hollowgasts.  These were invisible creatures that most thought to be soulless killing machines.  But Jacob had the ability to see and partially control the hollowgasts.  I loved how he came to understand and identify with these creatures.  It brought some humanity to other being that even the peculiars believed were strange.

And that is the beauty of this series.  In addition to action, suspense and a smattering of teen romance, you see how easily it is to categorize others into "peculiar", and "normal".  Jacob learns to see the hidden gift he possesses and develop it into a unique ability.  This is a lesson many of us need.  By recognizing our uniqueness, we can learn to value ourselves and gain the self-confidence needed to face life's ups and downs.  I thoroughly enjoyed this series for it's unconventional story-telling and it's humanity.  But start from the first book, or you won't understand what is going on!