In spite of the evident centrality of philosophical 'realism' in Collingwood's autobiographical account of his own intellectual development, his critique of 'realism' has hardly been investigated as a central theme in his philosophy. Collingwood's arguments against contemporary 'realism' and his stated move beyond 'idealism' have mostly been treated as a minor question subordinate to other questions. By contrast, I have tried in this thesis to reconstruct Collingwood's philosophy as a critical development of the realism/idealism dispute of his day, focusing on his less known early published and unpublished philosophical writings. This has enabled me to clarify his unique definition of 'realism' in terms of a dualistic framework, and underst...