The book I read is Ender’s Game by Orson Scott Card.  It was published in 1985.  The genre of the book is military science fiction.  I chose this book because there is a 2013 movie adaptation, and I wanted to know what the book was about before watching the movie. 
The protagonist of the book is Andrew “Ender” Wiggin, a six-year-old boy genius who is a Third, a third child in Earth's two-child policy.  Ender is selected by the International Fleet to save the world from the Buggers, an insectoid race that invaded the Earth twice and who the military vows to destroy.  Yet, as the story progresses it turns out the Buggers are not evil and they have no intention of invading Earth again, as the adults lead Ender to believe.  The antagonists of the book are the boys who bully Ender, to include Ender's brother, Peter.  Peter is a sociopath and threatens to kill Ender, “I could kill you like this, just press and press until you are dead and... I do mean it.” Ender is also lied to by the adults at Battle School and Command School.  While in Command School, they tell Ender one of the simulations is a graduation requirement, when in fact it is real and results in the Bugger race being annihilated.  “The adults are the enemy, not the other armies. They do not tell us the truth.” However, the adults are only doing their job and do not realize that the Buggers do not plan to invade again.  In this way, another antagonist of the book is the lies and misunderstandings.
The main conflict of the story is that Earth is on the brink of war with an alien race known as the Buggers.  The Buggers previously invaded Earth twice and now, the military's goal is to train a select number of intelligent children to form an army and destroy the Buggers.  The story begins with Ender on the operating table, having his "monitor" removed.  The monitor, a device implanted in the back of the neck, is used to monitor a child's view of the world as they do to determine if they are suitable for Battle School.  After Ender's monitor is removed, he is confronted by a gang of boys at school.  Ender retaliates to protect himself and ensure they will not bother him again, fatally beating the leader. "Knocking him down won the first fight. I wanted to win all the next ones, too, right then, so they'd leave me alone."  In response to this, Colonel Graff from the International Fleet knows Ender Wiggins is the one to fight the Buggers and save the human race.  Ender makes the tough decision to leave his home and go to Battle School.  He sees it as an opportunity to be free of his brother, although he is reluctant to leave his sister, Valentine, behind.  While in Battle School, Ender shows great promise.  He excels in Battle School and gets transferred to Command School, where he quickly becomes a commander of own army of young children.  However, the bullying continues.  On two occasions, Ender's temper gets the better of him and he seriously injures two bullies, fatally killing one.  The information about the death is kept from him.  While in command of his own elite army, Ender unknowingly ends the Bugger Wars.  The adults tell him it is a simulation, when in fact he has just destroyed the Buggers home planet and the entire Bugger race.             
The setting of the story takes place in the future on Earth and in space.  The story begins with Ender on Earth, but then it shifts to space when he goes to Battle School and Command School.  Between Battle School and Command school, Ender returns to Earth on leave.  After Command School, he goes to a planet colonized by Earth.  The author conveys that the story takes place sometime in 2090 because Ender tells Valentine about a computer not hooked up that was a century year old.  "Ancient things.  Installed back a century ago, when they made computers that didn't hook up with anything.”
The mood of the book is action-packed, while at times, dark and gloomy as the Earth is about to invade the Bugger home world.  At Battle School, the young children are train through a series of games.  These games are to prepare them for war.  Using zero gravity, they fly on various "stars" located in an arena and shoot at their opponents.  Two ways to win are to freeze your opponents, so they cannot fight back, or to reach the opponents home base.  The Earth has to destroy the entire Bugger race in order to survive human extinction.       
The author's purpose of the novel is to entertain, and perhaps teach a lesson or two to its readers.  The first lesson that lies and deception are the real enemies in battle.  The second lesson that even after one war is ended, another war may continue where it left off before it was interrupted.  This is evident by the fact that after the Bugger war, the United States and Russia go to war with one another again.
I believe this book deserves four and a half out of five stars.  It is very exciting to read and there are a lot of action scenes in the book.  The first thing I like about the book is the games Ender plays at Battle and Command Schools because they are fast moving and entertaining.  It is also interesting to see how Ender solves the challenges the adults give him.  I also like how the book focuses on many different perspectives and how, most of the time, they tie into the story.  In my opinion, the best part about the book is how Ender grows and matures as a six-year-old boy. The downsides of the book are that some plot elements are never explained, or they do not tie into the story.  For example, some time after Ender leaves home, Peter and Valentine proceed to make fake identities and discuss political issues, but it does not tie into Ender’s story and the Bugger War.  Overall, I enjoyed the story and felt it was a good book to read.

Backcover:
“I tell you, he is the one.”   Ender Wiggin, a six-year-old boy is recruited to be the savior of mankind.  After given the opportunity, he chooses to leave his home to train with the elite.  He says goodbye to his family and heads to Battle School.  But will he be able to stand up to the threats that await him?  Will he be able to face his own personal demons?  And will he be able to end the Bugger War?