The laughing baby tells about experiences and scientific findings and shows that laughter connects us with each other, that it is the background music of our successes, that it comforts us, that it elates us. Baby's first laugh is a magical moment. Parents always remember it. We know that a baby laughs more in the first two years than in all the years that follow, but why they laugh so much is little studied. Developmental psychologist Caspar Addyman has pursued this phenomenon with a large-scale study and concludes that laughter is evolutionarily ingrained in us and important to our early development. With laughter, he finds, babies communicate their successes to us, and it's worth pausing to consider how babies thrive and strive to achieve greater goals. Addyman chronicles prenatal development, making clear how the bond between mother and child builds immediately after birth, that the first smile is always authentic and an expression that the baby is happy, full and content. He interrogates psychoanalytic and philosophical concepts, explaining how babies become aware of their bodies through simple pleasures such as tickling and when bathed with splashes of water, what smiling during sleep means, the importance of touch and music, and that the game of peek-a-boo that excites all babies is pure social interaction.