The ISBNs of the three double volumes were , , and . In 2001, a single-volume abridgement of the full set of letters was published by John Murray (). The abridgement, made by Roger Hudson, received widespread and generally favourable reviews. Hudson added many extra footnotes for the benefit of a new generation of readers. A paperback version of this edition was later released by the same publisher (). In the USA, the original six volumes were published by Academy Chicago Publications. The single-volume edition edited by Roger Hudson was issued by the Akadine Press, .