Never Go Back by Lee Child

In an earlier book, ex-military man Jack Reacher talked to Susan Turner, the woman who has his old job, over the phone. He's intrigued by her voice  and heads back east to meet her. But when he gets there, he finds she has been arrested for taking a bribe. But that's just the beginning of the weird turns of events. Someone has re-enlisted him in the Army--and he may have a daughter out in California.  So begins another rollicking adventure with our independent hero in Never Go Back.

While there is some violence, because there's always some violence when Jack Reacher is around, there's also a lot of  trying to outwit the enemy with brainpower, which is what I liked about the earlier Jack Reacher books. (Some of the recent ones have been extremely violent.) It will be interesting to see where this series goes next as, near the end of the book, a somewhat melancholy Jack seems to be rethinking his solitary lifestyle.