AbstractRoot, tuber, and banana (RT&B) crops play a critical role in food and nutrition security in developing countries, increasingly so in sub-Saharan Africa (SSA). They have great potential to contribute to alleviate poverty, improve health and nutrition, and enhance the resilience of smallholder farmers to climate change. However, RT&Bs are characterized by unique challenges including vegetative propagation, genetic complexity, and postharvest constraints with bulkiness and perishability, compared to cereals. They are also characterized by a high yield potential and the ability to deliver micronutrients at large scale. However, until recently they have suffered from neglect in both investment and research. The CGIAR Research Program on Roots, Tubers and Bananas, which operated from 2012 to 2021, represented a novel and successful innovation model within the agricultural research for development domain not only in scientific terms but also from an organizational perspective. This program built upon the uniqueness of the RT&B crops and contributed to much of the progress reported in the book. This chapter provides an overview of challenges and opportunities facing RT&B crops in processing, marketing and distribution, enhancing productivity, and improving livelihoods. It presents underlying concepts for gender and scaling that feature prominently throughout the book, as well as an updated stance on innovation, touching base on the topic of the jobs to be done. The chapter concludes with an overview and highlights of the different sections and chapters in the remainder of the book.