This chapter will introduce the results of a comparative, interdisciplinary joint research on transdisciplinary research (TD), conducted by three social science researchers and three natural science researchers who work at the Decision Science Center for a Sustainable Society, Kyushu University (Institute of Decision Science for a Sustainable Society, Kyushu University, IDS3). Since the beginning of IDS3’s Future Earth project, or before the project became a global research program, all of us had engaged with TD research in our own local fields and disciplines, to solve local social problems while interacting with various social stakeholders. Our disciplines include public health, forest management, natural regeneration in paddy fields, small hydropower generation, local governance, and tourism promotion. While sharing the results of our TD projects among ourselves, we found some common questions and problem perspectives on Future Earth, mainly from the point of view of social science. In this chapter, we will present the outcome of our comparative joint research, including our common questions, perspectives, and problem setting on Future Earth and TD research. Then, we will propose some hypothetical indicators for the conditions and requirements for achieving successful “co-design/co-production/co-delivery.”