Like the Harry Potter books, this is for all ages of open-minded readers. I find that this appeals both to me now and to my inner 17 year-old. Of course it helps that I love time travel stories, esp. ones in which the hero goes back and forth trying to fix something, and naturally the point is that he has already done so, which means there's no paradox.

But there's more than just that puzzle here. There's some adventure, a bit of romance and humor, social and historical commentary, and elegant writing that doesn't talk down to teen readers. It's not perfect, but it's satisfying & thought-provoking.

"These windows too were open to the olive tree; the yellow scent was enough to stagger you."

I need to look up the Ludlow Massacre (the book taught me some history).

At one point the hero came in contact with a gang of 'tween boys, back in the 1910s when they could be on their own, camping out & cooking. The descriptions of their playful puppyish behavior mixed with the revelations of their competencies is a delight.

An invented text has this passage: "War, and particularly its aftermath, is nature's impassive way of testing our viability, to see whether we can evolve into a species that can dominate our ancient killer instinct. If we emerge strong and self-controlled, we may be fit to survive."
(I'm not sure I fully agree with that, but it sure is something to think about.)

I wish I'd bought this so I can keep it. I do plan to read it once more before taking it back to the library, because it's pretty hard to find and so I can't just tell myself to read it again 'someday.' I did buy [b:An Alien Music|3841227|An Alien Music|Annabel Johnson|https://i.gr-assets.com/images/S/compressed.photo.goodreads.com/books/1605010362l/3841227._SX50_.jpg|1785418] and will read it before passing it on, and I did find an enjoy the authors' "Grizzly" which is a 'boy's' adventure with no SF element. I will continue to hunt down more by the Johnsons, esp. the SF.

edit - The re-read was just as enjoyable and satisfying. Gosh. I have no idea why this isn't more popular. ( )

Humanity's been reduced to an underground existence. Aboveground is a scorched, UV-irradiated wasteland - but underground is sterile, regimented and hermetically sealed. The great hope of the future rests on the slim shoulders of genetically created, super genius children, but unfortunately they're dying young. For K/C-4(SCI) - Casey, for short - the answer lies in the past - but he's going to have to convince the powers that be that his risky time travel experiment will succeed in the time he has left: eight months and fourteen days.

But the past is hiding more secrets than Casey dreamed. Can he uncover them in time to save not only his colony, but himself?

Time travel books aren't my thing, but after a page or two I was hooked. ( )