Preface

Organoids are defined as three-dimensional structures derived from stem cells，progenitor，and/or differentiated cells that self-organize through cell-cell and cell-matrix interactions to recapitulate aspects of the native tissue architectures and functions in vitro.The application of organoids in scientific research is gaining momentum owing to their ability to model human organ development and various human pathologies in a dish.Specifically，human organoids offer advantages compared to animal models（such as rodents，which are commonly used）as they represent human physiologies and pathologies with unprecedented precision.Given this significant advantage，organoid technology is increasingly used in basic and medical research，with numerous applications in disease modeling，drug discovery，and personalized medicine.For instance，patient-derived cancer organoids enable rapid prediction of drug response in a personalized fashion.Combining organoids with cutting-edge technology，such as gene editing and organ-on-chips，have profound implications in fundamental biological research，biotechnologies，and disease treatment.The potential for organoids to revolutionize the field of medicine is immense，and the possibilities for their use are only beginning to be explored.

Chinese scientists have contributed significantly to the development of the field of organoid technology in the last 10 years，and their achievements are globally recognized.They have been successful in the construction of human blastocyst，pancreatic islet，liver，brain，cancer，and many other tissue organoids.These novel findings enable researchers to study the structure and functions of these organs in vitro，leading to a better understanding of the development and pathologies of these organs.Additionally，the creation of patient-derived organoids has facilitated the development of personalized medicine，and drug screening of various diseases has helped to identify potential new therapies.Furthermore，Chinese scientists have developed organoid transplantation，e.g.，transplantation of islet organoids in treating diabetic patients，enabling a promising direction for regenerative medicine.

Clearly，there is an urgent need for a book of organoids that would systematically introduce the current understanding and the important progresses made in the field over the past decade to researchers in different fields.Publication of such an academic book would not only provide knowledge in this fast-progressing field，but also communicate and disseminate it into a convenient and systematic format.It is timing that my Chinese colleagues have made the effort to organize such a book.

This book offers a comprehensive overview of organoids for multiple organs and cancer tissues.It outlines the progresses in developing nextgeneration organoid technologies，such as complex organoids with stromal cells and functional vessels and a human body-like system with multiorgan interactions.The challenges and future directions of organoid technology are also discussed.I am sure that this book will help researchers to learn the latest advances in the field of organoids and apply this knowledge to their own work.I wish that with the efforts from the whole international society organoid technology would provide more crucial theoretical foundations and practical solutions for disease treatment.(https://www.daowen.com)

Hans Clevers，MD，PhD

Professor in Molecular Genetics，Utrecht University，Netherland

Head of Roche Pharma Research＆Early Development，Switzerland

October 2023