This dissertation investigates public-public program collaboration (PPPC) between Head Start and the Virginia Preschool Initiative and asks why and how, and to what extent PPPC occurs between these preschool programs. To frame an understanding of PPPC, the dissertation assays collaborative process dimensions, collaborative management techniques, and degrees of collaborative activity. In-depth interviews with Head Start and VPI administrators result in the analysis of 16 Head Start-VPI dyadic relationships and places the focus of this research on the micro-level actions of the program administrators. Each Head Start-VPI dyad is assigned a degree of collaborative activity along a continuum ranging from no relationship (one dyad), cooperation (four dyads), coordination (six dyads), or collaboration (five dyads), and is assessed in terms of the presence or absence of the collaborative process dimensions of governance, administration, organizational autonomy, norms of trust, and mutuality. Qualitative comparative analysis (QCA) is used to identify the underlying process dimensions that comprise collaboration at the varying degrees of collaborative activity. Collaborating dyads generally are found to exhibit all of the process dimensions, where the no relationship and cooperating dyads exhibit relatively few of the process dimensions. Coordinating dyads typically have strong structural dimensions but weak mutuality, or strong social capital dimensions, but weak administration. The dissertation shows how public administrators engage the collaborative management techniques of activating, framing, mobilizing, and synthesizing, and finds variation in management techniques across types of collaborative activities. It also argues for activation activity to include "history of collaboration" stories and identifies six framing types that intersect at being collaborative or non-collaborative in focus and mature or immature. The dissertation concludes with recommendations for current preschool administrators and future scholarship.