In my last Ender post, I talked a little bit about the fact that I enjoy the "Shadow" series more than the "Ender" series. So I thought I'd start out by explaining what I meant by that. 
 Technically, there is just one series - the order goes like this: 
 Ender's Game 
 Speaker for the Dead 
 Xenocide 
 Children of the Mind 
 Ender's Shadow 
 Shadow of the Hegemon 
 Shadow Puppets 
 Shadow of the Giant 
 There are also a few new books in the series as of recently: Ender in Exile, Earth Unaware, A War of Gifts, and Shadows in Flight... but as I've only read up to Ender in Exile, we'll disregard these latest additions for now. 
 My argument is that there are two series. The Ender Series: Ender's Game, Speaker for the Dead, Xenocide, and Children of the Mind 
 And the Shadow Series: Ender's Shadow, Shadow of the Hegemon, Shadow Puppets, and Shadow of the Giant. 
 The Ender series follows Ender (obviously). The main problem I have with this part of the series is that after Ender's Game (and even towards the very end of that book) the story diverges itself from being an adventure tale and turns into this sort of philosophical discussion of the purpose of life. (There's nothing wrong with that - though Card's and my own perspective on that topic differ greatly - it's simply not my favorite sort of book/story to read). As such, this story also becomes more and more depressing the further you read. 
 The Shadow series, however, follows Bean and is much more of an adventure and less of a "let's debate the mysteries of the universe." It is a political thriller, a continuation of the mental gymnastics that we learn to love Bean for in Ender's Shadow (and, to a lesser extent, in Ender's Game, though Bean is a very small character in that book). 
 But back to my book review. 
 Ender's Game is about an Earth several hundred years in the future. Earth has been attacked by an alien race and nearly wiped out. There have been two attacks, and humanity has created a tenuous peace between nations to focus on figuring out a way to survive in a hostile galaxy. There is only one hope for the human race: its children. 
 The nations send their best and brightest, their youngest ones with the greatest potential to an orbiting space station called the Battle School. In this low-gravity environment, through games and lessons, the children are trained to become soldiers and generals while the teachers and the world watches with baited breath - hoping for just one child with the extraordinary mind that will be needed to defeat their enemy. 
 What do I think of this book? First of all, I love it. There are aspects of it I do not love, but overall, it is one of my favorite books. The writing is excellent, the story is well-told and clips along at a very nice pace. The heroes are genuinely likeable. 
 I read Ender's Shadow first, and I prefer it. Partially this is probably because I just like Bean better than Ender. 
 A word of caution: This is a book about children. But it is not a book FOR children. There is a lot of violence in this story. It is not pretty. But then, war is not pretty, nor should it be. There is a lot of crude language and unkindness between the kids. This permeates the first half of the story, and diminishes greatly in the second half of the story when everyone starts to buckle down and focus on the real enemy. 
 I think that is to some extent another reason why I prefer Ender's Shadow. Because Bean gets the children to remember who the real enemy is - and it is not each other, and it is not even the teachers. It is the alien race that threatens to destroy humanity. Perhaps it is just that Bean's story feels more like a sci-fi adventure, while Ender's story is far more introspective. When I'm reading for fun, I'd rather have the adventure. 
 I was asked last week how I felt about how the story uses the children to participate in war. My answer is simple: nothing about it is okay. And I believe that is part of the point of the story. The psychological trauma that Ender and to some extent all the Battle School children suffer is a great indicator that the author did not set out to write a story glorifying turning children into soldiers. I think the point was that children are smarter and more capable than they often seem. That their brilliance is in the way they see the world so differently from adults. And that it is the one of the truly great tragedies when a child has his or her childhood torn away from him or her. Even if it does mean the salvation of the planet. 
 Do I recommend this book? Yes, but not to readers under 18 without a parent's permission... and/or discussion of the book while reading it with a parent. 
 But I'd start with Ender's Shadow.