It's the 4th ed. Actually now that I looked harder it's might not be 44 it might be 39. It gives dates for 1st, 2nd, and 3rd editions. Then it says "Fourth edition revised and reset. published august, 1939" (also the last copyright was 1939 too). Then, "Eleventh Printing, December, 1944." So it's one of those years. Hope that's helpful!