All impressions are broadly similar and feature Thror's Map and the Map of Wilderland on the endpapers. Includes four colour illustrations in addition to the eight standard black and white illustrations. When the Third Edition was issued the impression numbering was continued on from the previous edition, i.e. starting from the 15th Impression not from the 1st. They were not re-numbered until 1968. There appears to have been an error made when the details of the new edition were recorded. What should have read as: Fifteenth Impression 1965 
Third Edition (Sixteenth Impression) 1966 was actually set down as: Third Edition (Fifteenth Impression) 1966 
Sixteenth Impression 1966 This error was never corrected. There are eight impressions of the Allen & Unwin Third Edition recorded between 1966 and 1972, but only seven of these actually "exist" - see above. While all are similar in most respects there are a few differences. The impression numbers were: 1st (15th) Impression 1966 - does not exist. 
2nd (16th) Impression 1966 - the "real" first impression. 
3rd (17th) Impression 1967. 
4th Impression 1968 - Impressions re-numbered here. 
5th Impression 1970 - Two illustrations re-located within text. 
6th Impression 1971. 
7th Impression 1972.