The essays in this volume from liturgists in mainstream Christian churches in Australia and New Zealand gladly acknowledge that when we pray, we join with others. We share a history, a way of worshipping, often a common language and established forms, with authorised prayer books designed to retain the theological and liturgical emphases of the various churches. Yet it is a subject that can divide as well as unite; with a variety of experiences, attitudes and aspirations, especially in a world where forms of worship are readily accessible from internet sources. If worship and prayer express what we believe, who authorises forms of worship; who determines the authenticity of liturgy; what principles underlie and surround how people of faith worship in formal gatherings? These are some of the issues that inform the essays in this practical and ecumenical resource.