"Zero to Three" is a single focus bulletin of the National Center for Infants, Toddlers, and Families providing insight from multiple disciplines on the development of infants, toddlers, and their families. Noting that knowledge of childrens musical experiences in context is central to understanding childrens lives, and that reciprocally, knowledge of current trends in fields such as early childhood development and neuroscience informs interpretations of childrens musical experiences, this issue focuses on ideas for using what is known about the musical lives of children to promote and protect childrens healthy development. The featured articles are as follows: (1) The Musical Lives of Young Children: Inviting, Seeking, and Initiating (Lori A. Custodero); (2) Musicality and Music before Three: Human Vitality and Invention Shared with Pride (Colwyn Trevarthen and Stephen Malloch); (3) Mothers Are Musical Mentors (Sandra E. Trehub); (4) Lullabies and Playsongs: Why We Sing to Children (Laurel J. Trainor); (4) Music in the Time of Toddlers (Danette Littleton); (5) From Mozart to Motown, Lullabies to Love Songs: A Preliminary Report on Parents Use of Music with Infants Survey (PUMIS) (Lori A. Custodero, Pia R. Britto, and Tao Xin); and (6) The Toddler Top 40: Musical Preferences of Babies, Toddlers, and Their Parents (Elissa Johnson-Green and Lori A. Custodero). Also included are an annotated list of musical resources (Beatriz Ilari and Elissa Johnson-Green) and a description of a center for children in families in North Carolina (James Sexton). (HTH)