The Enemy – Lee Child

In 1989 Jack Reacher was an MP – as the New Year, and the last decade of the century, dawns the political landscape is set for a power shift, for the Berlin Wall is coming down, and with it the end of the Cold War. Recently relocated to North Carolina, Reacher has every expectation of an uneventful segue to 1990, until gets a call from the local police – a soldier’s been found dead in a nearby hourly rate motel.
When the body turns out to be that of a two-star general – one who should have been in Europe, no less – Reacher’s antenna pings. This becomes an alarm bell when his death knock to the general’s widow instead turns up another body. Ad thus begins a covert investigation into the armed forces itself – an investigation that starts the career-oriented Reacher on his path to roaming righter of wrongs.
The Enemy is something of a departure from the seven preceding Reacher novels – the first to entirely flashback, it gives us a far more fully fleshed picture of the often enigmatic lone wolf regular readers have come to almost know. We meet Joe, his older brother (previously encountered in the first Reacher novel, Killing Floor, under very different circumstances):

I hadn’t seen him for more than three years. The last time we’d been together was for our father’s funeral. Since then we had gone our separate ways.
…He was two years older than me, and he always had been, and he always would be. As a kid I used to study him and think, that’s how I’ll look when I grow up. Now I found myself doing it again. From a distance we could have been mistaken for each another. Standing side by side it was obvious that he was an inch taller and a little slighter than me, But mostly it was obvious he was a little older than me. It looked like we had started out together, but he had seen the future first, and it had aged him, and worn him down. … I didn’t know what he did for a living. He had probably told me, it wasn’t a national secret of anything. It was something to do with the Treasury Department. He had probably told me all the details and I probably hadn’t listened. Now it seemed too late to ask.
“You were in Panama,” he said. “Operation Just Cause, right?”
“Operation Just Because,” I said. “That’s what we called it.”
“Just because what?”
"Just because we could. Just because we all had to have something to do. Just because we’ve got a new Commander in Chief who wants to look tough.”…
“You got Noriega yet?”
"Not yet.”
"So why did they post you back here?”
“We took twenty-seven thousand guys,” I said. “It wasn’t down to me personally.”

I know this doesn’t look like much, but there’s so much foreshadowing here, for The Enemy (even the title) and for Reacher, that I found it a really clear example of how intelligent Childs’ writing is – though the books look like fairly standard action novels there’s really subtle layering there.
Joe and Reacher are flying to France, in response to an uncharacteristic summons from her doctor. The scenes here, and the occasional passing reference to her in chronologically later books, are the only glimpses we have of Josephine Reacher née Moutier and her effect on our hero; they serve to contextualise Reacher’s unwavering commitment to doing the morally right thing as a family tradition, while embedding the presence in the present of the past.
Josephine is dying, of cancer she chose a year ago not to treat. The scenes where Joe and Reacher talk about intervention and, a page later, where she talks about ho and why she made her decision, are beautiful. They articulate no only generational and cultural differences in attitudes to life and death but also grief, loss, and mourning.

“Won’t you miss us, Mom,” [Joe] asked.
“Wrong question,” she said. “I’ll be dead. I won’t be missing anything. It’s you that will be missing me…You’re really asking another question… You’re asking, how can I abandon you? You’re asking, aren’t I concerned with your affairs any more? Don’t I want to see what happens with your lives? Have I lost interest in you?”
We said nothing.
“I understand,” she said. “Truly I do. It’s like walking out of a movie. Being made to walk out of a movie you’re really enjoying. That’s what worried me about it. I would never know how it turned out. I would ever know what happened to you boys in the end, with your lives. I hate that part. But then I realized, obviously I’ll walk out of the movie sooner or later. I mean, nobody lives for ever. I’ll never know how it turns out for you, I’ll never know what happens with your lives. Not in the end, Not even under the best of circumstances. I realized that. Then it didn’t seem to matter so much. It will always be an arbitrary date. It will always leaving me wanting more.”

Although for me these elements of family, character development and context, including the way and the why of Reacher’s departure from the institution he’d previously been part of from birth, are the centre pieces of The Enemy, they're surrounded by an engrossing, somewhat far-reaching and far-fetched but sadly believable conspiracy-based plot. - Alex

The Jack Reacher novels
Killing Floor; Die Trying; Tripwire; The Visitor; Echo Burning; Without Fail; Persuader;The Enemy; One Shot;The Hard Way; Bad Luck and Trouble; Nothing to Lose; Gone Tomorrow; 61 Hours; Worth Dying For