In this book, Max Thurian again returns to the central theme of his work: ecumenism. Here, however, he is concerned with practice rather than with the theory of Christian unity, and his approach, as the title of the book suggests, centers around the sacrament of the Eucharist. Since the act of Communion is the basic exterior manifestation of interior faith, he argues, it should be particularly susceptible to ecumenical interpretation and application--an application which would take the form of ""intercommunication,"" by virtue of which the members of one Christian church would be allowed, and even encouraged, to take the sacrament in other Christian churches. In that context, Thurian sets out the essential lines of a common eucharistic theology, one on which most (though not all) of the Christian churches could agree, and touches briefly on corollary themes such as a common Christian ministry. What the author proposes is, of course, already in practice in the ""underground churches"" of Christendom -- notwithstanding the prohibitions of pastors and popes -- and one may assume that it is only a matter of time until the practice emerges into public view and, hopefully, public acceptance. In the interim, however, it is helpful to have at hand the beginnings of a theology of intercommunion, particularly in the concise, rational and persuasive form that is Thurian's trademark.