The National Institute of Mental Health (NIMH) maintains a comprehensive portfolio of research on depression risk, etiology, pathophysiology, intervention, and services research. This broad portfolio exists because, as with many of our illnesses, there is still much work to be done to identify potent intervention targets for treatment and prevention, develop novel interventions, optimize the effectiveness of the interventions we know to be efficacious, and develop the science to implement and sustain programs that work. With the goal of expediting scientific advances, NIMH encourages investigators in a given field to communicate, collaborate, and share knowledge, data, and resources. The papers presented in this special issue highlight a concerted, grassroots collaborative effort among the investigators in the field of depression prevention that resulted in a proactive, thoughtful sharing of ideas and sharing of individual-level data across studies. For the field, this collaboration presents an opportunity to Bsee the forest through the trees^and develop an understanding of the state of the science for depression prevention that goes beyond what we can learn from the report of an individual study.The papers included in this special issue were authored by prevention scientists who are developing and testing interventions-some specifically targeting depression, others targeting associated high-risk behaviors. Reading the papers as a set enables one to identify common findings and themes and allows us to see if an individual study's effects change when participantlevel data is combined and re-examined across a range of studies. This collaboration offers innovations not just in the data analysis and methodology, as described in the papers by Siddique et al. (2017) and Brincks et al. (2016), but also in our understanding of how we might enhance or alter existing interventions so we may more effectively prevent the incidence or recurrence of depression among vulnerable youth. The papers go beyond reporting only if an intervention works, but also for whom. A focus on moderators as well as possible mechanisms of action will further our ability to refine intervention strategies and, ultimately, prevent incidence of illness.In the interest of space, we will not review all of the individual study findings but will, instead, highlight a few key outcomes across the papers. In doing so, we see that early intervention matters. Stronger effects tend to be found for groups who received interventions in earlier grades or earlier in the course of illness (i.e., before symptoms emerged). The set of papers also shows the ways in which family can be a key component to effective depression prevention. Across studies, aspects of the family moderate intervention effects-e.g., parent illness, parent marital status, and overall family functioning. In one study, family characteristics were more important than dose with respect to impact on internalizing behaviors (Mauricio et al. 2016).This special issue also includes an article by Brown a...