This book discusses a multidisciplinary and multi-stakeholder collaborative approach to small population clinical trials. It provides and illustrates a systematic framework that depends upon a collaborative infrastructure between the patient community, patient advocacy groups, researchers and investigators, pharmaceutical companies, global regulatory agencies, and customers. The book also highlights the considerations of natural history and patient registry, diagnostic criteria determination, identification of clinically meaningful endpoints, and global regulatory guidance. The authors detail the nuances of clinical trial design as specific to small population disease, drawing from real examples.