This paper describes the challenges and opportunities that older Americans face, with a focus on retirement income security and the role of continued work later in life. We begin with an overview of the new world of retirement income security in America, including a discussion of how a low return environment (e.g., low interest rates) exacerbates existing retirement income security challenges. We then document how older Americans have responded to the evolving retirement income landscape, especially when and how they exit the labor force, and we explore how continued work later in life can help mitigate some of the anticipated retirement security challenges. We then pose some important outstanding questions. The implications of societal aging depend in large part on how we harness or squander the labor resources of older Americans.