As a footnote to the text provided by Mary Humphries:-

The National Library of Scotland is celebrating in 2006 the 50th anniversary of the opening of the George IV Bridge Building by the Queen on 4th July 1956, and to mark the occasion their website each week this year is featuring an item to represent the highlight of collections acquired in each of the past 50 years.

For 1957 the highlighted acquisition is the Panmure Music Books amongst which is the Commonplace Book of Robert Edward, which was the ultimate source of Ewan MacColl's text for Sheath and Knife.