I haven't read Radical (though I will read it soon). My impression is that that is a better book (I'll let you know). Basically this is a book with some good advice for churches and church leaders about making a difference in the world. Platt is an evangelical deeply committed to the Great Commission, but also in moving his 4000 person church to tangilbly care for those in need. He advocates that churches eveluate their programs in light of the Great commission and see what is helping them do that. He argues that Christians need to do works in response to God's grace, that the word of God is central, that the church functions by its membership (not just the beautiful people on stage), we are responsible to evangelize the whole world so that Jesus will come back, and God is passionate for his glory.
I disagree with him on several points, but the thrust of Platt's book seems good. Evangelicals have sometimes ignore taking up any responsibility for God's kingdom. And I share Platt's concern for justice and making a difference in the world.
So why does this book make me so tired? This book really emphasizes the activist dimension to the Christian life. Good in as far as it describes this well (okay not super well, this book lacks a little in the beauty department). But it would be sad if this dimension to the Christian life was all there was.