This newly published book by John Piper, The Future of Justification, A Response to N. T. Wright, is now available for free from the Desiring God website, here.
These are Piper's words from the introduction,
"My little earthly life is too far spent to care much about the ego gratification of scoring points in debate. I am still a sinner depending on Christ for my righteousness before God. So I am quite capable of fear and pride. But I do hope that, where I have made mistakes, I will be willing to admit it. There are far greater things at stake than my fickle sense of gratification or regret. Among these greater things are the faithful preaching of the gospel, the care of guilt-ridden souls, the spiritual power of sacrificial deeds of love, the root of humble Christian political and social engagement, and the courage of Christian missions to confront all the religions of the world with the supremacy of Christ as the only way to escape the wrath to come. When the gospel itself is distorted or blurred, everything else is eventually affected. May the Lord give us help in these days to see the word of his grace with clarity, and savor it with humble and holy zeal, and spread it without partiality so that millions may believe and be saved, to the praise of the glory of God’s grace".