Environmental toxicity and sustainability are major areas of research for the leather industry, as well as for the larger luxury and fashion industry. Several alternatives to traditional animal-based leather have been introduced in the market as “vegan” leather, e.g. the pineapple skin leather Piñatex, mycelium (mushroom leather), apple leather, cactus leather, and PU/PVC faux leather. However, a clear assessment of the sustainability (e.g. carbon/water footprint, LCA) for these alternatives is missing. The aim of this book is to provide clarity and a coherent structural assessment of sustainable vegan or vegetarian alternatives of leather. This book contributes to the current research within sustainability and environmental impact, production, and consumption aspects of these materials.