Since the discovery of plastics several decades ago, the widespread consumption of plastic products and their subsequent inappropriate disposal and accumulation have recently generated new societal concerns of waste management due to their inherent slow degradability, high volume increase and low recycling rates, which are negative on the basis of self-sustainability. Regulations imposing waste reduction, reuse and recycling indices and responsibilities, as well as effective collecting system and the development of new, environmentally clean recycling technologies are some of the efforts to achieve the self-sustainability goals. The efficiency of the collection and sorting systems impacts directly on the amount of recycled plastics and on their cleanness and quality, therefore, enlarging their market potential. The development of new recycling technologies is diversified and can be classified into mechanical, chemical and energetic recycling. In mechanical recycling, successful technologies are achieved through the improvement of existing processes using additives, blends with other plastics and alternative processing routes in order to maintain the original properties of the virgin resin and even allowing them to return to the same application as originally intended. Chemical recycling processes to obtain intermediary products for new polymers become feasible due to the cost reduction of the raw materials involved. Lastly, despite the under use of the gross energy potential of the raw materials employed, energetic recycling plants are gaining a proportion of residues whose technological solutions for separation and/or reprocessing are deficient, but which, on the other hand, are voluminous, consequently solving the problem of both residue accumulation in densely populated regions and their respective insufficient energy supplies. In this book, the authors proposed to present an overview of the current state of this whole plastic recycling sector including their recent advances, and highlighting new markets and recent trends on recycling technologies around the world. However, mechanical recycling has been emphasised owing to the experimental and published work of Manrich's workgroup at the 3R Residues Recycling Center, which has concentrated on studying all the steps in the process of mechanical recycling.