In this book, the concept of the circular economy is examined from the point of view of textile-to-textile recycling, with strong consideration of the latest political objectives. Readers will gain an understanding of the basic principles and implementation possibilities, and discover which textile-to-textile recycling solutions have already been implemented in industry and which solutions are promising for the future. Thus, this work is the starting point for readers who want or need to contribute to saving our environment through concrete actions. The process chain of textile production and recycling is first presented. Based on this, concepts for textile-to-textile recycling are explained and deepened using industry examples. These concepts are further developed and finally implemented as strategies for a transformation into a circular economy. Global fiber production is growing continuously and with it its negative impact on our environment. Although the share of recycled fibers is also increasing, it is mainly linear bottle recycling; the share of pre- or post-consumer textile recycling remains less than 1% of the fiber market. With an international authorship from both industry and academia, and reader-friendly presentation including many illustrations and in-depth practical examples, this book identifies possible solutions to these challenges.