The domain-specific approach to working memory assumes specialized working memory systems dedicated to maintaining different types of information (e.g. orthographic, phonological, semantic, visuospatial) which serve to support processing in that domain. These storage systems are assumed to be separate from long-term memory representations in each domain and also from attentional and cognitive control processes. This chapter provides an overview of support for this approach drawn mainly from neuropsychological case study and case series approaches, though it also integrates findings from behavioural and imaging studies of healthy individuals that were motivated by the neuropsychological findings or provide confirmation of those findings. The neuropsychological findings not only demonstrate dissociations between working memory in different domains but also provide a rich source of evidence to address the nature of forgetting in working memory, the interactions between working memory and long-term memory, and the role of aspects of working memory in language comprehension and production.