According to Worthpoint, “17 editions [were] published between 1934 and 1963 in English”. WorldCat has the 1934 edition being self-published, with subsequent versions being published by a range of houses.
Difficult to obtain nowadays, though Amazon US is currently listing a copy of the 1946 edition with a price reflecting its rarity.
Copies are kept in major libraries including SOAS. We have been unable to find any further information online.