In this article, I present a review and tutorial of the literature on closed-loop supply chains, which are supply chains where, in addition to typical forward flows, there are reverse flows of used products (postconsumer use) back to manufacturers. Examples include supply chains with consumer returns, leasing options, and end-of-use returns with remanufacturing. I classify the literature in terms of strategic, tactical, and operational issues, but I focus on strategic issues (such as when should an original equipment manufacturer (OEM) remanufacture, response to take-back legislation, and network design, among others) and tactical issues (used product acquisition and disposition decisions). The article is written in the form of a tutorial, where for each topic I present a base model with underlying assumptions and results, comment on extensions, and conclude with my view on needed research areas.