The Church is a mystery.  Believers who want to enter more deeply into that mystery will reflect on the Church's basic characteristics, the "marks of the Church": what it means for the Church to be one, holy, catholic, and apostolic. Non-Catholics and nonbelievers looking to appreciate how Catholics regard the Church also will desire to understand these "marks". 

In this book, renowned Dominican theologian Fr. Aidan Nichols explores the Church's characteristics. Drawing on insights from four theological masters-Henri de Lubac, Jean Tillard, Hans Urs von Balthasar, and Charles Journet-Nichols seeks to help Catholics and non-Catholics to "figure out" the Church, on at least a fundamental level. The four masters in question do not claim to exhaust the mystery of the Church, nor does Nichols. They do, however, assist the reader in going deeper into the mystery.

To accomplish this goal,  Nichols appeals to both the Scholastic tradition and authors influenced by the ressourcement movement in theology. In this way, he provides readers with a sense of Catholicism's breadth, which is at once orthodox and yet generously conceived. 

"Fr. Nichols takes an extremely complex and important topic -- the Church's holiness, unity, catholicity, and apostolicity -- and delivers a marvelously limpid, succinct, and balanced theological portrait.  He lovingly illuminates the Church herself, the mystery of communion with the God the Father in Christ and the Holy Spirit.  No contemporary work on the Church comes close to the level of Father Nichols's achievement here." 
- Matthew Levering, Chair of Dogmatic Theology, Mundelein Seminary 

"A brilliant explanation of the characteristics of the Church.  Nichols offers the reader a clear summary of the ‘marks' that are the key to apologetics and ecclesiology."
- Fr. Kenneth Baker, SJ, Author, Inside the Bible

"This work draws together the seminal contributions in twentieth century and contemporary ecclesiology.  Nichols is sensitive to the different nuances found across the spectrum of theological traditions, including Eastern Orthodoxy.  It is simply the best work available for understanding the fundamental elements of Catholic ecclesiology.  It is also a case study in how to present scholastic material without putting readers to sleep. Nichols can be read for the sheer beauty of his prose."
- Professor Tracey Rowland, John Paul II Institute, Melbourne, Australia