I just saw a copy of this book on Ebay and noticed that the 2nd Impression Return of the King had "Second Impression" printed on the spine of the dust-wrapper.

My first edition copies of the LOTR in dust-wrappers don't have any indication of the Impression on the Spine, so I was interested to see if anybody knows how long this practice went on for and which impressions were involved?

2nd Impression Return of the Ring Wrapper