This white paper, developed in partnership and with funding from The World Bank, examines Call Detail Records (CDRs) and their expanding role in providing insight into human behavior, movements, and social interaction. After providing additional contextual elements (Part 1), the paper summarizes current legal frameworks (Part 2), before exploring structural socio-political parameters and incentives structuring the sharing of CDRs (Part 3), proposing guiding ethical principles (Part 4) and discussing operational options and requirements (Part 5).