This is from my Amazon review of J. Alec Motyer, The Message of James: The Tests of Faith (Bible Speaks Today) from 15 November 2002.
Alec Motyer is one of the best biblical expositors out there. His greatest strength in biblical scholarship has been in the structure of biblical works, something most people have found entirely lacking in James. Motyer reconstructs what may well have been the connections in the mind of James between seemingly unrelated teachings. In this book, James no longer seems to be a collection of miscellaneous proverbs but is more a summary of a thought process that moved from one thought to the other very quickly and without explicitly tracing the connections, but Motyer shows the connections behind such moves.
The unity of the book of James thus comes out very strongly, and Motyer's thesis that James is a summary of a sermon or series of sermons makes much sense. On the level of details, Motyer does a great job explaining the text and its significance for daily life. He explains the theology behind James's thinking, something many scholars have assumed is not present in this book, and he presents his material in an easily readable manner without sacrificing the quality of his comments or the grounding of what he says in the actual text of James and the light of biblical theology.
This is certainly not the most in-depth commentary on James or maybe even the best. The work by Luke Timothy Johnson in the Anchor Bible series and Douglas Moo's Pillar Commentary (as opposed to his earlier, more brief Tyndale volume) are probably the best works on this epistle. However, Motyer is an excellent place to start for a more popular level and provides a nice complement to those works.