In the past fifteen years, a great deal has been learned about the particular challenges of distant collaboration. Overall, we have learned that even when advanced technologies are available, distance still matters (Olson and Olson 2000). In addition, a recent seminal study of sixty-two projects sponsored by the National Science Foundation (NSF) showed that the major indicator of lower success was the number of institutions involved (Cummings and Kiesler 2005; chapter 5, this volume). The greater the number of institutions involved, the less well coordinated a project was and the fewer the positive outcomes. There are a number of reasons for these challenges. For one, distance threatens context and common ground (Cramton 2001). Second, trust is more difficult to establish and maintain when the collaborators are separated from each other (Shrum, Chompalov, and Genuth 2001; Kramer and Tyler 1995). Third, poorly designed incentive systems can inhibit collaborations and prevent the adoption of new collaboration technology (Orlikowski 1992; Grudin 1988). Finally, organizational structures and governance systems, along with the nature of the work, can either contribute to or inhibit collaboration (Larson et al. 2002; Mazur and Boyko 1981; Hesse et al. 1993; Sonnenwald 2007). This chapter describes our attempt to synthesize these findings and enumerate those factors that we (and others) believe are important in determining the success of remote collaboration in science. In working toward a theory of remote scientific collaboration (TORSC), we have drawn from data collected as part of the Science of Collaboratories (SOC) project, studies in the sociology of science, and investigations of distance collaboration in general. The Developing Theory Success We begin by discussing what we might mean by success in remote collaboration, since in the literature it can vary from revolutionary new thinking in the science to simply having some new software used. Different sets of factors may lead to different kinds of success. These outputs include effects on the science itself, science careers, learning and science education, funding and public perception, and inspiration to develop new collaboratories and new collaborative tools. The details are listed in short form in table 4.1. Effects on the Science Itself Early goals for collaboratories included that they would increase productivity and the number of participants, and democratize science through improved access to elite researchers (Finholt and Olson 1997; Hesse et al. 1993; Walsh and Bayma 1996). Similar assumptions were made with regard to interdisciplinary research (Steele and Stier 2000). These goals have to date not been tested. Today, scholars, policymakers, and scientists no longer take these assumptions for granted. Increasingly, they recognize that to define and evaluate the success of distributed and large-scale scientific collaborations is a complex task. Traditional measures of success in science are geared toward the individual, and include metrics such as producti...