A superb presentation of Christianity's answer to this question.
If you wonder about God, the Bible, or Heaven--this book is a must read. For Evangelical Christians, this is an excellent book to give to people who are searching, wondering, questioning spiritual areas of existence. This is simply written, a quick read (1-2 hours) and presents the Bible's response to the question posed in the title. An excellent precursor to other written material that provides more in depth information on what the Bible says.