The Spirituality of the Cross by Gene Edward Veith

I love this book because it really lays out the important Lutheran doctrines in a way that's easy for people to understand. It clarifies what distinguishes Lutheranism from other denominations. There are many people who like to think all religions are the same or at least that all Christian denominations are pretty much the same, but that isn't the case. But this book explains why Lutheran Christians believe the way they do about Justification, Law and Gospel, the Means of Grace, Worship, etc. What a wonderful resource!