The Graveyard Book

The Graveyard Book
By Neil Gaiman

This is a spooky story of a young boy named Nobody Owens, raised by ghosts in a graveyard after his family is murdered one night...the killer, a creepy man named simply Jack, continues to search for the toddler who escaped from the house.
Luckily, the ghosts who adopt Bod, as Nobody is nicknamed, are protective and kind, and offer him all...or almost all...of the "comforts" a boy would need growing up.  He has many bizarre experiences and adventures with otherworldly beings before he must confront the murderer of his family...

Laika

Laika
By Nick Abadzis

Illustrated by Hilary Sycamore

Even if you're not a dog lover, you will probably enjoy this bittersweet graphic novel.  It's based on the true story of the first animal to orbit the Earth--launched there by the Soviet Union in 1957 on Sputnik 2.  This little stray, named Kudryavka but known to the world as Laika the Soviet Space Dog, was also the first animal to die in orbit. 
Read the story of the scientists and caretakers of Kudryavka, and experience the tension between a competetive drive for scientific understanding and a respect for life...you might need some kleenex.  I did.

Ender's Game

Ender's Game
By Orson Scott Card

Ender Wiggins is six years old when they take him away from his family on Earth and put him in space-based Battle School.  There, he meets other gifted children like himself, all being trained to fight the "buggers"--the supposed alien enemy.  Ender quickly rises to the top, becoming the best chance Earth has in the space war against the buggers.  Meanwhile, his brother and sister on Earth, also gifted, are planing to take over the world and start an Earth-based war.
This is an intense, action-packed, but pretty serious sci fi novel about adults using children as soldiers, the threat of invasion from other worlds, and the purpose of war.  I couldn't put it down!
There are more books in the Ender series, too, but I haven't read them yet.