Throughout this book, information has been presented and described on potential approaches for allowing the circular economy to increase in implementation and impact and, at the same time, on underlying mechanisms that help to improve processes from physical-chemical and thermodynamic points of view. Likewise, efforts have been made to show the evolution over time of the circular economy; to establish the theoretical foundations for circular economy 3.0, which seeks to maximize value retention of resources; to replace virgin material inputs with secondary resources and to launch new business model incentives; and to describe the 10Rs hierarchy of the circular economy value proposal. The 10Rs are refuse, reduce, resell/reuse, repair, refurbish, remanufacture, repurpose, recycle, recover, and re-mine. The understanding provided by the last point is necessary to classify efforts that can contribute to the practical implementation of the circular economy.