This book studies the doctrinal development of the Pali Nirvana and subsequent tradition and compares it with the Chinese Agama and its traditional interpretation. The author clarifies early doctrinal developments of Nirvana and traces the word and related terms back to their original metaphorical contexts, elucidating diverse interpretations and doctrinal and philosophical developments in the abhidharma exegeses and treatises of Southern and Northern Buddhist schools. The book finally examines which school, if any, kept the original meaning and reference of Nirvana.