Follow The Sun (FTS) has interesting appeal - hand-off work at the end of every day from one site to the next, many time zones away, in order to speed up product development. While the potential impact on "time-to-market" can be profound, at least conceptually, FTS has enjoyed very few documented industry successes because it is acknowledged to be extremely difficult to implement. In order to address this "FTS challenge" we provide here a conceptual foundation and formal definition of FTS. We then analyze the conditions under which FTS can be successful in reducing duration in software development. We show that handoff efficiency is paramount to successful FTS practices and that duration can be reduced only when lower within- site coordination and improved personal productivity outweigh the corresponding increase in cross-site coordination. We also develop 12 research propositions based on fundamental issues surrounding FTS, such as: calendar efficiency, development method, product architecture and hand-off efficiency, within-site coordination, cross-site coordination, and personal productivity. We combine the conceptual analysis with a description of our FTS exploratory comparative field studies and draw out their key findings and learning. The main implication of this article is that understanding calendar efficiency, hand-off efficiency, within-site coordination and cross-site coordination is necessary to evaluation - if FTS is to be successful in reducing software development duration.