Book excerpt: Surveying the barriers that contemporary thinking has erected between the natural and the supernatural, between earth and heaven, Hans Boersma issues a wake-up call for Western Christianity. Both Catholics and evangelicals, he says, have moved too far away from a sacramental mindset, focusing more on the "here-and-now" than on the "then-and-there." Yet, as Boersma points out, the teaching of Jesus, Paul, and St. Augustine -- indeed, of most of Scripture and the church fathers -- is profoundly otherworldly, much more concerned with heavenly participation than with earthly enjoyment. In Heavenly Participation Boersma draws on the wisdom of great Christian minds ancient and modern -- Irenaeus, Gregory of Nyssa, C. S. Lewis, Henri de Lubac, John Milbank, and many others. He urges Catholics and evangelicals alike to retrieve a sacramental worldview, to cultivate a greater awareness of eternal mysteries, to partake eagerly of the divine life that transcends and transforms all earthly realities.