This book is an outgrowth of the field research on the phenomenon of breastmilk insufficiency in Esmeraldas, Ecuador (2008). Theoretically speaking, in these pages, the reader will find a constant link between the cultural and biological spheres, thus further developing the interdisciplinary theory on the breastmilk insufficiency phenomenon. Methodologically speaking, this book is based on data from a prospective longitudinal study. This work is expected to contribute not only to the literature of human biology and medical anthropology, but also to the fields of geography, demography, medicine, nursing, physiology and psychology, among others.

This book's specific aims are threefold: first, to elucidate, define, and analyze the phenomenon of breastmilk insufficiency. Second, to show breastfeeding data from a Latin America region –for scholars to have more data to examine breastfeeding's human ecology. Third, to share the first-hand methodology and fieldwork techniques used for many years, that can be replicated in further research.

Moreover, this book broadens the ideas gleaned from the study of breastfeeding to biological and cultural phenomena in general. Characterizing the interaction between biological and cultural factors as a dance, these two types of factors are explored in detail, while arguing that that they are not only inextricably linked, but that they are part and parcel of a whole phenomenon made up of the interaction between the two. It is also argued that this dance is fundamentally changing the human experience, in terms of both biology and culture –which have become so intertwined that they should be given a new name, "culbios."