The Philosophy of Spiritual Activity is a major philosophical work by Rudolf Steiner examining human thought, knowledge, freedom, morality, and spiritual development. Steiner explores how human beings experience the world through perception and thinking and considers the role of conscious thought in forming an understanding of reality.

The book develops a philosophy centered on individual freedom and ethical self-determination, arguing that genuine moral action arises through conscious insight rather than external authority. Combining epistemology, ethics, psychology, and metaphysical reflection, the work provides an important foundation for Steiner's later philosophical and spiritual writings.