God brought many wonderful things out of the Reformational time beginning in 1517, but the most central and important Gospel aspect that we hold today is the doctrine of faith alone. We believe, in distinction form the Roman Catholic Church, that we are saved by grace alone, through faith alone, in Christ alone. In the book, Faith Alone: The Evangelical Doctrine of Justification, R.C. Sproul gives a detailed explanation of that subject. He successfully and convincingly demonstrates that the doctrine of justification by faith alone is an essential and fundamental aspect of our beliefs. You should be able to describe in a few sentences what justification by faith alone is and means, and this book will help you do just that.