There are about forty excerpts from a Who’s Who of Christian theologians (Luther, Calvin, St. Thomas, Wesley, C.S. Lewis, etc.). Needless to say, there is some good stuff in here; there’s also a biography, bibliography, and questions for each.
Note: I did not read the whole book (my notes don’t say why). I read the first section (“Preparing for the Spiritual Life,” eight authors), and then the selections re Pascal, St. Francis, E. Stanley Jones, Wesley, Bonhoeffer, Calvin, Kierkegaard, and Luther.
Note also that the publisher is the same as for 25 Books Every Christian Should Read, discussed elsewhere on this site.