Over the last few decades, biopharmaceuticals have transformed many areas of healthcare and have given hope and extended the lives of many patients. Curative treatments, however, remain elusive in most cases. This book describes strategies to develop improved versions of biopharmaceuticals (“biobetters”) to bridge the gap between existing therapies and curative therapies. With an aim to stimulate research and development in a wide array of therapeutic areas, diverse topics are covered, including the following: tissue specific targeting of enzyme replacement therapies; the development of novel protein structures with the potential to improve upon critical attributes of current monoclonal antibodies; the modification of current monoclonal antibody designs to improve their in vivo stability; and finally, the economic and regulatory considerations for the development of biobetters.