The quantitative research question is: Does one dose of Play2Sleep delivered during home visits with mothers and fathers of 5-month-old infants with infant sleep disturbances reduce the number of night wakings at age 7 months? The qualitative phase will focus on explaining the quantitative findings by asking: What are parental perceptions of family experiences, processes, and contexts related to Play2Sleep and infant sleep? The overarching mixed methods research question is: How do parental perceptions of family experiences, processes, and contexts related to infant sleep explain the effectiveness of Play2Sleep?