This book deals with themes concerning religious education and the spirituality of children. Throughout the seventeen chapters, the book stimulates a scholarly discussion about children and theology. The book makes clear that classical Christian theology can benefit from taking seriously children's voices and reflections about children. The volume demonstrates how nuanced and interdisciplinary reflections can be relevant for Christian and social practices of adults with children and how these practices can influence theology. This volume asks the following questions: - Why is it important that we hear the 'voices of children' and what does this mean for how we treat children and relate to them? - What do the 'voices of children' express? How do children experience society and, in particular, religion, and what do they have to say about it? - What do the 'voices of children' mean for theology, ethics and religious education? In what way can our theology change when we see reality from the perspective of children? This book consists of five parts. In the first part the reader receives an overview of the current challenges concerning children and spirituality.The two chapters of this part offer an introduction to contemporary thinking about children, theology and spirituality and the place of 'children's voices' within this scope. The second part refers to biblical sources for contemporary theological reflection on children. The third part contains pedagogical and ethical reflections on children, as well as a view from practical theology about children in the world and the responsibility of churches. This third part looks mainly at children in relation to society, both in the past and in the present. The fourth part focuses on children living in the family, which is seen as a domestic church. The fifth part takes up the theme of children's spirituality again, showing children's own spiritual reflection and ways of theologizing with children in church and family contexts, by communication, literature and all forms of religious education and/or catechesis.