To survive, organizations need to produce and process information about their environment, for instance, about customers, competitors, suppliers, governments, or all kinds of socioeconomic and technological trends. The process of obtaining this information is often called competitive intelligence (cf Fleisher & Blenkhorn, 2001; Kahaner, 1997; Vriens, 2004). An important stage in the competitive intelligence process is the collection stage. In this stage, one has to determine relevant sources, access them, and retrieve data from them (cf Bernhardt, 1994; Kahaner). For each data class, many possible sources are available, and determining the right ones is often difficult. Moreover, accessing sources and retrieving data may require a lot of effort and may be problematic (cf Cook & Cook, 2000; Fuld, 1995; Kahaner, 1997). In this chapter, we present a tool for supporting the effective and efficient use of sources: the source map. In essence, a source map links data classes to sources and contains information about these links. This information indicates the adequacy of sources in terms of ease of access, ease of retrieval, and usefulness of the retrieved data. A source map can support the selection of appropriate sources and it can support the assessment of the overall adequacy of available sources.