Is that first grin a reflex, or the beginning of a social smile? This warm, evidence-aware guide helps parents understand how infant smiles develop, what they communicate, and how to enjoy early connection without turning a flexible milestone into a test. You will learn why newborns may smile in sleep, how a social smile usually emerges around six to eight weeks, and why some babies take longer or express engagement in quieter ways. Clear explanations cover corrected age for babies born prematurely, the roles of vision, hearing, temperament, alertness, and familiar voices, plus simple ways to invite face-to-face interaction without pressure. You will find observation prompts, realistic examples, and guidance on when to mention persistent concerns to a pediatrician or health visitor. The book also respects families whose babies communicate differently, and parents living with anxiety, exhaustion, grief, or uncertainty. Rather than promising that smiling creates perfect happiness, it shows how responsive attention can support a growing relationship while leaving room for every baby’s individuality. Part of The Smile and Happiness Library.