The early years in the life of a child are critical for cognitive, social and emotional development. It is therefore important that we make sure that children grow up in an environment where their social, emotional and educational needs are met. Children who grow up in an environment where their developmental needs are not met are at risk for compromised health, well-being and sometimes developmental delays. Society must therefore work to ensure that children develop in safe, loving and secure environments. This yearbook compiles the work done in 2011 with a broad research agenda on a global basis, addressing questions ranging from policy to practice, and spanning the developmental spectrum from human genetics, infancy and early childhood, to adolescence and adulthood.