While drug discovery for common disorders is somewhat standard and based on the large potential markets, the small market for most orphan diseases means that effective therapies are uncommon. With next generation DNA sequencing, the pace of inherited novel rare disease gene identification has increased markedly. Drug discovery for rare diseases is somewhat hampered by a lack of collaboration between academia and industry separating the necessary resources from skills. This volume discusses important aspects of orphan drug development such as regulatory affairs, public industry partnership, bench to bedside using examples of rare diseases, challenges of clinical trials and future directions.