All of the authors in this special issue have different views and definitions of collaboration, often depending on the purpose of their collaboration efforts or the requirements spurring the collaboration such as Head Start-Child Care partnerships. What is common among the articles is that all researchers focused on two or more early care and education staff or programs working together toward a common goal and most of the articles described formal collaborations that were defined by regulations, policy, administrative requirements, and in some cases, funding. Notably, none of the articles described the role of states or state-level early childhood policies or systems. This is an important area of further research, because states can set the stage for effective collaboration and coordination at the local level. More importantly, they can help to support collaborations across programs to ensure equitable access to the social capital and networking that often results from long-standing collaborations. (author abstract)