Industrial symbiosis, a subfi eld of industrial ecology, engages traditionally separate industries and entities in a collaborative approach to resource sharing that benefi ts both the environment and the economy. This chapter examines the period 1989-2014 to "take stock" of industrial symbiosis. First, we look at the earliest days to discuss what inspired industrial symbiosis both in the scholarly literature and in practice. Next, we draw attention to certain dilemmas and sharpen the distinctions between industrial symbiosis and some related concepts such as ecoindustrial parks and environmentally balanced industrial complexes. With regard to dissemination of industrial symbiosis ideas, we found that at the country level, China has now received the most attention in industrial symbiosis academic research and this continues to grow rapidly.The fi nal section looks at both theory (conceptual knowledge largely from academia) and practice (on-the-ground experience of public, not-for-profi t, and private organizations working to implement industrial symbiosis) as both are essential to industrial symbiosis. A bibliometric analysis of the scholarly work, capturing 391 articles indexed in Scopus and Web of Science for 20 years between 1995 and 2014, is used to defi ne and track the types of articles, how the mix of articles has changed over time, and what the most popular journals are. Taking a closer look at the research literature, distinct themes are identifi ed and discussed such as the scale of industrial symbiosis, whether industrial symbiosis is based on planning or selforganization, the role of social factors, and what is known about the actual performance of industrial symbiosis. To assess important issues with regard to practice, we compile a list of industrial symbiosis-related events from database searches of reports, media, and key consulting and business organizations and examine trends, mechanisms, and motivations of industrial symbiosis practice by surveying key practitioners and academics.