A Christian knows he is a Christian and has no doubt that he is. He may not, however, know all the details about his salvation. He may not know why God made him sinful. He may not know how Christ's death and resurrection affect him.
There may be many things he does not know about his salvation. Entering The Kingdom: Knowing Every Detail About a Christian's Salvation was written to explain these details. It explains in simple and straightforward language all the details regarding a Christian's salvation and how he became part of the kingdom of God.
When a Christian learns these details, he will understand who he is as a member of God's kingdom and how he should live within it. A Christian can then glorify God and fulfill God's purpose for their lives.