Along with that high concept, we also get some interesting structure to the book. Parts of it are numbered and give us the voice of the entities (it's not really clear on how many are involved, but their sections always use a "we") who have burdened Junior with the ultimate fate of Earth. Not only do they tell him things but they also narrate a portion of his life. We also get sections from the viewpoint of the major characters in the book - Junior, his family, and Amy, whom he loves and loses.
It's not a very happy book, unsurprisingly. There is addiction, abuse, cancer, mental illness, and lots of pain. But there is also happiness. And baseball.
There is a science fiction element to this book as well. Junior happens to be the fourth smartest person in the world and under his guidance, ships are built to allow many people to escape the coming apocalypse. But Junior doesn't escape. Instead...well, that's something to be discovered by reading the book.
This is a book worth reading, for the ideas and for the quality of writing. I had a hard time putting it down and I have a feeling I will be thinking about it for quite a while.