The current book covers my research team and other scientific research founds on chemical recycling of polyethylene terephthalate (PET) wastes chemical recycling and converting the wastes to the valued intermediates as well as starting materials which usable in the production of PET and other industrially interest chemicals namely, polyesters, polyols for polyurethanes and etc., in addition the effects of various reaction conditions as well as catalysts from micro to nano dimensions, on the PET chemical recycling have been covered in this book. One of the main goals in publication of current art work is motivation of PET producers, consumers and related industries to avoid landfilling and/ or leaving the PET wastes in the environment and the main author believes that the publishing of this book can penetrate knowledge based researches in industry especially in the undeveloped and third world countries. In the writing of this book we tried to demonstrate our goals in simple and understandable templates for all academics and industries.