I am not a school student anymore, but when I wanted clarification of certain Biblical doctrines, a friend of mine pointed me to this book. This book was written by Dr. Millard J. Erickson, a widely respected Evangelical professor of theology, and is widely used as a textbook throughout the United States. The book is divided into twelve parts: 1) The Doing of Theology (studying and contemporizing theology), 2) God's Revelation, 3) The Nature of God, 4) The Work of God, 5) Humanity , 6) Sin, 7) The Person of Christ, 8) The Work of Christ, 9) The Holy Spirit, 10) Salvation, 11) The Church (nature, government and ordinances), and 12) The Last Things (eschatology).
Unlike what you might expect from a textbook, I found this book to be very readable, with the issues being spelled out in easy to read language, with the different views of the doctrines being explained, with the author then focusing in on his view and how and why it differs from the other views. Overall, this book answered my questions quite nicely, giving me a much better understanding. So, even if you are a simple layperson like me, you will benefit from having this book. I highly recommend it.