The Baby and the Couple provides an insider’s view on how infant communication develops in the context of the family and how parents either work together as a team or struggle in the process. The authors present vignettes from everyday life as well as case studies from a longitudinal research project of infants and their parents interacting together in the Lausanne Trilogue Play (LTP), an assessment tool for very young families. Divided into three parts, the book focuses not only on the parents, but also on the infant’s contribution to the family. Part 1 presents a case study of Lucas and his family, from infancy to age 5. With each chapter we see how, in the context of their families, infants learn to communicate with more than one person at a time. Part 2 explores how infants cope when their parents struggle to work together – excluding, competing or only connecting through their child. The authors follow several case examples from infancy through to early childhood to illustrate various forms of problematic co-parenting, along with the infant’s derailed trajectory at different ages and stages. In Part 3, prevention and intervention models based on the LTP are presented. In addition to an overview of these programs, chapters are devoted to the Developmental Systems Consultation, which combines use of the LTP and video feedback, and a new model, Reflective Family Play, which allows whole families to engage in treatment. The Baby and the Couple is a vital resource for professionals working in the fields of infant and preschool mental health including psychiatrists, psychologists, social workers, family therapists and educators, as well as researchers.