"For the Life of the World: Sacraments and Orthodoxy," by Alexander Schmemann, is a significant work for understanding the Orthodox--and therefore ancient Christian--view of sacraments and sacramental living. Two additional essays, written in the early 1970s: "Worship in a Secular Age," and "Sacrament and Symbol," are fitting appendices to the title work, which was originally published as a study guide for a 1963 National Christian Student Federation conference.
Schmemann states that we were created to live in a sacramental relationship with God and the creation, but this life was lost in the Fall of Adam and Eve. Christ, who gave his life "for the life of the world," came to restore this sacramental relationship, not only with God, but with all of Creation.
Schmemann writes that the purpose of the book "is to remind its readers that in Christ, life--life in all its totality--was returned to man, given again as sacrament and communion, made Eucharist." He goes on to discuss the importance of this understanding for our mission in the world.
I know many individuals who have wondered how the Eastern Orthodox and Christians in the West (both Roman Catholic and Protestant) can use the same terminology and mean different things. Sometimes the differences are subtle, sometimes radical. Schmemann believes that secularism is at the heart of those differences, and that secularism was born when scholars in the West sought to analyze, define and explain the sacraments, most significantly the Eucharist (or Communion).
By picking apart the meaning and "the elements" of Communion, scholasticism allowed the Eucharist to be divorced from the context of the Liturgy. Therefore, in order to satisfy an increasingly scientific approach, the West began to separate the sacred from the secular. As stated above, Christ came to restore the sacramental life as it was intended in the Garden. Schmemann maintains that separating the secular from the sacred is a Christian heresy that needs to be confronted. (By the way, he confronts this tendency among the Orthodox as well.)
I would do a disservice to this important work if I were to continue this inadequate description. It's significant that many--if not most--of the customer reviews on Amazon identify themselves as non-Orthodox readers. An Anglican reviewer quoted on the back cover states that "this is one of the best introductions to the sacraments, and not simply the 'Eastern' view of them."
"For the Life of the World" appears on many lists of books intended to introduce Orthodoxy, however in my opinion it would best suited to readers who have at least a little background in theology or Church history. As suggested above, this might be the best volume for getting a better understanding of why some of the terminology between East and West differs. Therefore, this would be a great book for improving dialogue between the many traditions of Christianity.
For additional reading, try "The Mystical Theology of the Eastern Church," by Vladimir Lossky or "The Orthodox Way," by Bishop Kallistos Ware.