Over a remarkably brief period, the concept of cognitive liberty has transformed from a countercultural rallying cry to an internationally debated legal norm. This chapter traces the emergence and evolution of the concept from its initial appearance in the writings of Boire and Sententia to its reception and refinement by various scholars and its internationalization and institutionalization in legal documents. It also analyzes the relation of cognitive liberty to freedom of thought and offers some speculative thoughts about analysis its future, especially the prospects for the recognition of a novel right to cognitive liberty at the domestic or international level.