Walter Kasper's ecclesiological approach reflects the Church in the tension between vibrant plurality (human freedom) and necessary unity (the essence and purpose of the Church). Stefan Ley presents Kasper's eucharistic communio-ecclesiology in terms of its genesis, systematic position, and implications for both theoretical and practical ecclesiology. Special attention is given to the concept of communio as well as the dispute with Joseph Ratzinger regarding the relationship between the universal Church and local churches.