Luther for Armchair Theologians
2.5 stars out of 5. The book would more properly be titled "The Gospel According to Luther," as the author focuses on Luther's theological evolution towards the understanding of the Gospel that caused him to nail his theses to the church door and work out his understanding of the Gospel in everyday life. I have become more interested in the Luther's views on work recently, and that is mentioned toward the end of the book.
In many places it is not clear what thinking is the author's and what is Luther's. Luther said a lot of disturbing things or supported some causes that in hindsight were not very Gospel-centered (as this website shows). But the author doesn't give much biographical information as the context for these or explain their theological underpinnings. That said, his quotes from various Luther writings inspires the reader to dig deeper.
This is the third Armchair Theologians book I have read. It contained some cursory biographical material, mostly at the beginning and end (paraphrase, "oh, by the way, he got married and it meant a lot.") I would recommend reading something like Civilization of the Middle Ages for the pre-Lutheran context so you can better understand Germany and the state of doctrine in the Roman Catholic Church when Luther came onto the scene.