In November 2015, Pope Francis called on theologians to explore whether normal Catholic practice should be changed to allow Christians, belonging to other churches, to share fully at the table when they take part in a Eucharist celebrated by Catholics. Thomas O'Loughlin provides his contribution to that challenge in this volume. He argues that the various ways of thinking about what we are doing in the liturgy should lead us to see intercommunion as enhancing our participation in the mystery of the Church and the mystery we celebrate.