from Allen & Unwin in the UK: The plain brown with gold
lettering on the spine is the 1960 edition for the Reader's Union
bookclub. The next set is the 1974 "second impression" set, and
the last is an all-in-one paperback Unwin issued in 1978 with a Bakshi
movie tie-in - a bit of trivia being that this last one is the version
that Peter Jackson had from his youth and spoke fondly of.