Oxytocin is a mammalian hormone that also acts as a neurotransmitter in the brain. Oxytocin is a peptide of nine amino acids (a nonapeptide). It is best known for its roles in female reproduction: it is released in large amounts after distension of the cervix and vagina during labour, and induction of milk ejection in facilitating birth and breastfeeding. Recent studies have begun to investigate oxytocin's role in various behaviours, including social recognition, bonding, anxiety, trust, and maternal behaviours. This book gathers the latest research from around the globe in this field.