The book provides a study of the work of Gu Yanu (1613-1682), the founder of the textual-critical method of "studying the foundations" in Chinese science of the Qing era. Particular attention is paid to the biography of Gu Yan, his works and an encyclopedic review of the Confucian tradition. The value of Gu Yanu's philosophical views lies in the reliance on a thorough study of ancient Chinese classical canons and commentary literature of subsequent eras.