Robert Letham writes well and I like the fact that (as he did with his book on the Trinity) he surveys the material both from a biblical and an historical perspective. One caution (for those who but books on the strength of endorsements, is that I am not sure everyone would understand the "pastoral sensitivity" that Packer refers to in the same way as he does. I think he is right but some may be expecting something different than what they get. But what you get is worth it. And full marks to Letham for reminding us of the importance of this aspect of biblical doctrine. I highly recommend it.