This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations. Research has shown that young babies - well before they form their first bond to a caring adult - enjoy participating in groups and group processes. Babies in Groups examines the consequences of these findings for science, for early education practice and policy, and for adult psychotherapy. The authors report research showing the extensive capacity of preverbal infants for group-communication in all-baby trios and quartets, backed by findings about primate sociability, the social brain, cultural histories, and human evolution. These studies open up new ways of imagining human development as fundamentally group-based. In addition, the authors explore the changes that a group-based vision of infancy could bring to early child education and care. They also show how ignoring group contexts in many clinical traditions can distort descriptions of what happens in therapy, producing such unintended consequences as 'mother-blaming' for the future problems an infant may experience as she or he grows up. Finally, the book's appendix summarises the main forms of evidence which falsify claims that science has proven that an inborn gift for dyadic 'intersubjectivity,' or for one-to-one infant-adult attachments, founds human social development.