As this issue of the "Future of Children" makes clear, there is much yet to learn about military children and their families. A big part of the reason, write Anita Chandra and Andrew London, is the lack of sufficiently robust sources of data. Until more and better data are collected about military families, Chandra and London say, it will be difficult to study the breadth of their experiences and sources of resilience, distinguish among subgroups within the diverse military community, or compare military children with their civilian counterparts. After surveying the available sources of data and explaining what they are lacking and why, Chandra and London make several recommendations. First, they say, major longitudinal national surveys, as well as administrative data systems (for example, in health care and in schools), should routinely ask about children's connections to the military, so that military families can be flagged in statistical analyses. Second, questions on national surveys and psychological assessments should be formulated and calibrated for military children to be certain that they resonate with military culture. Third, researchers who study military children should consider adopting a life-course perspective, examining children from birth to adulthood as they and their families move through the transitions of military life and into or out of the civilian world.