This document examines support for students in open learning systems (OLS) by clarifying the concept at the theoretical level, looking for empirical support for its potential value, and identifying key variables that constrain approaches to support. Part 1 clarifies two key concepts--support and effects. Part 2 presents the definition of OLS. In Part 3, a structured overview of approaches toward support is presented, resulting in a multidimensional categorization. The demand for or necessity of support facilities is discussed in Part 4. Part 5 introduces the discussion of "functions" of support. Parts 6 and 7 structure the empirical results in relation to the potential benefits of support approaches. First, results are discussed in relation to the OLS. Next, an overview is provided of research results outside the context of OLS that extend the findings presented in Part 6. This two-sided approach to the discussion helps to clarify strengths and shortcomings of support-related research in OLS and implies the integration of the support dimensions, the support functions, and the support effects in terms of study success and persistence. The conclusions in Part 8 lead to a priority list for a research agenda in relation to support in OLS. (Contains 107 references.) (Author/YLB)