Mobile phone tracking data collected by telecommunication companies allow recording and reconstructing the practices of mobilities and the presence of users with significant spatial-temporal detail. If properly managed, analysed, and possibly combined with other sources of information, mobile phone data can represent an interesting opportunity for urban research and mobility studies as they shed light on complex socio-territorial dynamics difficult to infer from conventional data analysis. At the same time, reports of numerous experiments using these sources reveal some of the challenges that researchers face in accurately capturing the behaviours of individuals through digital data and translating them into useful research knowledge. Refer...