Volume 4 includes unique records of Orok (Uilta), a Tungusic language (dictionaries, texts, grammatical comments) noted down by Pilsudski directly from native informants at the beginning of the 20th century on Sakhalin. The original source material is identified with the help of - and confronted against - all the existing contemporary dictionaries with the assistance of leading specialists in the field (the Novosibirsk Avrorin group, also called the school of Manchu-Tungusologists). Abundant comparative data are quoted. All necessary introductory information and commentaries of ethnographic, historical, and linguistic nature are provided. Archival photos taken by Pilsudski are juxtaposed with related contemporary photos especially taken for this purpose. In addition, samples of original manuscript pages are reproduced. Bibliographical data and indices are provided in conformity with the previous volumes.