In the After is an interesting amalgam of a book -- a book that started out as a post-apocalyptic survival story, then shifted to a psychological thriller, then to a sci-fi action story. Though I prefer my genre mash-ups to be a little more well-blended, I still think that there is a lot here that will appeal to YA readers.As the book opens, Amy's world is coming to an end -- aliens have landed in Central Park, and half of the people on the planet are dead. Amy's parents never return to their Chicago home, and her life becomes a lonely tale of scavenging and hiding. She's able to survive because her dad outfitted her house with solar panels and her mom insisted on an electric fence and lessons for her tween daughter at the shooting range. (Yes, this all requires quite a bit of suspension of disbelief, but I was okay with it.)After a month of this, Amy finds Baby, an abandoned toddler, in a grocery store. The two of them develop an interesting relationship that was one of my favorite parts of the book. In order to keep the aliens at bay, they have to be absolutely silent, so they stop speaking and develop their own sign language. As years go by, the two of them become as close as a parent and child, or sisters. Their relationship was both touching and a little creepy.And then … their situation changes. I don't want to say more, because part of the fun of the book for me was the suspense. But the middle part of the book had me glued to my kindle as I tried to figure out what the heck was going on with Amy and Baby. Since Goodreads lets me hide spoilers, here were my theories: 1) Baby is imaginary OR 2) Baby is an inanimate object, like that soccer ball in the Tom Hanks movie where he's shipwrecked. 3) Baby is an alien OR 4) Baby is Amy's child with an alien. If you don't want to read the spoilers, let's just say that I became unsure as to whether Amy was a reliable narrator.The final third of the book began to display some twists and turns I'd seen before. And … of course the book ended in the requisite cliff-hanger.Still, I definitely enjoyed In the After. It was truly suspenseful and truly creepy at times. The psychological aspects -- Amy's odd relationship with Baby and Amy's seeming unreliability -- were my favorite parts of the story. Plus, Amy and Baby were the only two characters who seemed realistic and three-dimensional to me -- the rest seemed to be there just to fulfill a plot function. Since this story is almost three different stories stuck together -- post-apocalyptic+ psychological thriller + sci-fi -- I'm guessing that different readers will have very different opinions. Stop by my blog , YA Romantics, and give me your take -- my full review goes up June 17 -- or leave them in comments.