If you haven't read The Twelve-Fingered Boy by Jacobs, stop here. Don't even read the description of The Shibboleth, because it won't make sense to you now, and contains too many spoilers for you to enjoy the first book properly.
"There are certain shibboleths to our condition."
At the end of the first book of The Twelve-Fingered Boy Trilogy, Jack and Shreve are incarcerado—physically locked up. Shreve's back in the custody of the state of Arkansas, and Jack's somewhere in the clutches of Mr. Quincrux—both problems Shreve aims to rectify.
Cages might hold Shreve's body, but the power that's been growing since his encounter with Quincrux has reached a pinnacle. Nothing can prevent his mind from scaling the etheric heights. Freed from his body, Shreve discovers the magnitude of the evil that's stirring in the east. The wave of insomnia that's paralyzed the nation is only the beginning.
To save Jack—and maybe all of the humanity he no longer feels part of—Shreve has no choice but to join Quincrux and the Society of Extranaturals.
The Twelve-Fingered Boy started off like any number of books about a teenage boy incarcerated for something he did, in fact, do, although he is not at heart a bad kid. At first, it is just about surviving in the juvenile detention system, then slowly slips into the paranormal abilities of Shreve, Jack, and others.
The Shibboleth is firmly planted in the paranormal. While both boys are still under lock and key, that is almost a minor nuisance compared to what is going on in their minds, and in the minds of thousands of people across the country - some gifted with paranormal abilities, but most the victims of some as yet unnamed being. Characters from the first book reappear, and there are some twists as to who the good and bad guys are. Jacobs' writing has definitely improved - he never lost my attention as he did a couple times in the first book.
A trilogy worth picking up for any middle or high school library, and handing off to teens into paranormal adventures that involve more mind power than romance and renegade fae.