This book compiles a wide range of topics relevant to studying the use of both innovative and conventional plant breeding methods to develop new varieties of grass and bast fiber crops under various environmental conditions for sustainable fiber production. The book contains 20 chapters supported by 153 color figures and 61 tables. The chapters are grouped into two parts. Part I, subtitled Grass Fiber Crops, covers the genera Dendrocalamus, Hordeum, Zea, Avena, Sorghum, Saccharum and Triticum. Part II, subtitled Bast Fiber Crops, covers the genera Musa, Linum, Cannabis, Apocynum, Corchorus, Hibiscus, Opuntia, Pongamia, Crotalaria, Cissus, Areca and Acacia. Each chapter discusses breeding techniques for specific species or a group of related species. Topics covered include current cultivation methods and challenges, biodiversity, germplasm conservation, breeding methods including conventional, molecular, tissue culture, genetic engineering, gene editing, hybridization, and mutation breeding. Each chapter concludes with future research directions and a comprehensive list of references for further reading. Seventy-nine globally recognized scientists from 11 different nations contributed to the chapters based on their expertise in the subject. The chapters underwent a thorough review process to ensure scientific accuracy and presentation quality. The book is a valuable resource for professional plant breeders and geneticists, researchers, entrepreneurs, and graduate students who are interested in biotechnology, molecular breeding, and agriculture. .