UPDATE: Minutes after posting the above I received in the mail a publication of the Christian Counseling & Educational Foundation called Seasons. This issue features a brief interview with Powlison about his new book. Here's his response to the question, "Why this book? Why right now?":
I think the time is right for a book that takes a new look at what biblical counseling is at its best: a way of talking and acting that moves us toward God and one another. Speaking Truth in Love is the most practical book I have written, but also the most comprehensive. I think many people are looking for something deeper, more profound, and more redemptive from the community of Christ than what they have experienced. They have glimpsed what it could be like to live in a community where the faith, love, sacrifice, and wisdom that God has given one person flows towards others so that the whole community grows together. Speaking Truth in Love is a guide to speaking and living together in this redemptive way.