The leading historian Keith Sorrenson has collected in three volumes the complete correspondence (174 letters in all) between two distinguished twentieth-century Māori scholars and statesmen, Sir Apirana Ngata and Sir Peter Buck (Te Rangi Hiroa). 'The letters confirm that each man was indeed a totara tree of some magnificence and that each was a tree that stood alone. Even today such trees remain rare, ' writes Hirini Moko Mead.