This was a complex Science Fiction book written as a sequel to Ender's Game. This one isn't for children because it has a few more adult themes. (Really adults don't want to read about these things either!) Anyway despite it being a bit graphic when it comes to "murder" in the alien part of the book it was interesting to imagine the world Card creates for our reading enjoyment. Where does he come up with this stuff?
So in this book, without giving much away, Ender is thousands of years old but because of space travel is only 35. He travels to different worlds populated by humans to Speak the truth for the dead. He finds out everything he can about a person that died and then spells it all out, the good, the bad and what the person could have been but didn't. This is in place of a eulogy.
He wrote a book about the Hive Queen (the alien leader whose world he blew up without knowing he was really doing it or destroying a whole alien race). This story is the truth and people all over the Hundred Worlds in the universe read it and kind of start a following or religion. They don't know Ender wrote it because he just signed it Speaker For The Dead. Anyway, he gets invited to a planet that has another alien race and saves the day! (can't give away the story here). He also finds another alien and becomes friends with her.
Overall the book was complex and mysterious. I think it should have been called Ender Holmes Science Fiction Mystery. But it is just classified SF. I think it would be really weird to live on a planet other then Earth.