This book was formerly available in English in a terrible translation. I didn't know how bad the translator did until I read this "Reader's Version." It makes me angry to think that such a great piece of Christian literature suffered for so long because of a poor (hard to understand) translation. During seminary training, Lutheran students are often told that they should reread Law and Gospel throughout their ministry. The "Dau" translation made that a ponderous and unlikely-to-fulfill task; the "Reader's Version" by contrast is a delight and refreshing exercise.
C.F.W. Walther is considered the greatest Lutheran theologian America has ever produced. His greatness, in my opinion, was formulated by his early suffering from bad theology. In this, he was similar to Luther! When Walther was a student in German, his first awakening to Christianity was at the hands of Pietists. He is able to show the beautiful comfort of the gospel and how Pietism undermined it while trying to produce sincere Christians.
This "insiders'" view was especially interesting to me because I have often heard the charge that someone was a "pietist" when it seemed to me that the so-called "Pietist" was simply a pious Christian. People who have a regular prayer life, or do independent Bible study (or small group Bible study) are victims of this misunderstanding. Walther devoted a lengthy discussion on the way that Pietism stressed the spiritual struggle that was necessary BEFORE a person was directed to Christ. Since people were pointed to their personal struggles and told they weren't ready for Christ, Pietism was withholding the gospel that Christ sent us to preach.
One of my favorite portions of Law and Gospel (even when I only read it in the old translation) is when Walther compares preachers that don't direct their sermons at the hearts of their hearers to hunters going in the woods and shooting their guns into the air and calling that hunting!
Law and Gospel has the best treatment of the "sin against the Holy Ghost" that I have ever read: clear, Scriptural, and thorough.
The "Reader's Version" has excellent supplemental information. The "Glossary" would be an interesting publication, even without the book, because it explains many historical or peculiarly Lutheran terms in an informal, essay style that gives a reader with no background an appreciation for what a Lutheran insider takes for granted, and Lutheran insiders will learn background that no one ever took the time to tell them. There is a timeline on the development of understanding of Law and Gospel in the Christian church, an expansive biography of Walther, and other historical helps -- all of which contain fascinating revelations alongside need-to-know facts.