Retirement involves a set of institutional arrangements combined with socio-cultural meanings to sustain a distinct retirement phase in life course and career pathways. In this Introduction to the Special Issue: 'Reinventing Retirement: New Pathways, New Arrangements, New Meanings,' we outline the historical development of retirement. We identify the dramatic broad-based changes that recently have shaken this established construct to its core. We describe the main organizational responses to these changes, and how they have been associated with shifting, multiple meanings of retirement. Finally, we present a model that frames two general forms of reinvention of retirement. The first involves continuation of the idea of a distinct and well-defined period of life occurring at the end of a career trajectory, but with changes in the timing, the kinds of post-retirement activities pursued, and meanings associated with this period of life. The second represents a more fundamental reinvention in which the overall concept of