Finishing up Christianity & Liberalism by J. Gresham Machen. It was given to me by a good friend of mine. Written in the early 20th century, he clearly spells out how the liberal movement in Christianity misses it.
For being almost a hundred years old, it reads like it was written yesterday in so many ways. A quote sums up the spirit of the book.
"Christ died"--that is history; "Christ died for our sins"--that is doctrine. Without these two elements, joined in an absolutely indissoluble union, there is no Christianity." (p.23) He explains well what he means by this, and the implications are far-reaching.
Considered on of the top 100 books of the millennium by World magazine. I can see why.