During the early twentieth century, British novelist and philosopher May Sinclair published two book-length defenses of idealism. Although Sinclair is well known to literary scholars, she is little known to the history of philosophy. This paper provides the first substantial scholarship on Sinclair's philosophical views, focusing on her mature idealism. Although Sinclair is working within the larger British idealist tradition, her argument for Absolute idealism is unique, founded on Samuel Alexander's new realist beliefs about the reality of time. Her metaphysics (...) takes idealism and pantheism in new directions and provides fresh insight into 1920s debates between British idealisms and realisms. (shrink)