When a newborn smiles, is it a glimpse of happiness, a sleep-related reflex, or the early work of a developing nervous system? The Newborn Smile offers a clear, reassuring guide to the first months of facial expression, helping parents distinguish spontaneous movements from emerging social communication without turning ordinary variation into a cause for worry. You’ll explore how REM sleep, feeding, digestion, sensory input, facial muscles and the maturing brain can shape those fleeting grins. The book also explains when smiles typically become more responsive, how premature birth affects developmental timing, and what to notice alongside expression—such as eye contact, alertness, movement and response to voices. Practical observation tools, gentle interaction ideas and question prompts for pediatric appointments help families follow development without testing or performing for their baby. Warm, evidence-aware and respectful of every infant’s pace, this book replaces guesswork with informed attention while making room for delight, uncertainty and rest. Part of The Smile and Happiness Library.