Like a lot of people I have read every Jack REACHER book (in order).
In too Deep is a low point in the series. Too many gaps and less Reacher being Reacher. Its almost like he is fallible and normal as he is most often not in prior adventures. Boring at times and confusing at others.
Once I pick up (Kindle) a Reacher novel I struggle to put it down, I read this one in small bites.
Hope things improve.