In a recent book on the historical development of Buddhist thought, the author, David J. Kalupahana, has presented the thesis that early Buddhist philosophy, as found in the Pali Nikāyas and Chinese Āgamas, is radically different from that of later Buddhism, and supports his claim by tracing the historical divergence of the later schools from original Buddhism as he reconstructs it. He then goes on to assert that not only does early Buddhism differ philosophically from the later schools, but also that even the spiritual goal of nirvāna was fundamentally different, i.e., that the experience or condition denoted by the term ‘nirvāna’ in early Buddhism is quite different from that state which the same term came to denote later – a theory which is perhaps the most controversial feature ofhis overall interpretation of Buddhism.