Archibald 'The Grim', 3rd Earl of Douglas

We are probably all familiar with this depiction of Archibald The Grim.  Until now, I was unaware that it is taken from of 'The Book of the Medieval Knight' published by Cassel PLC. It was published in the 20th century, so not the book of more recent origin.

Can anyone help me identify a seller of this publication?

Archibald Douglas, known as "The Grim" or "Black Archibald," was a powerful Scottish lord in the late Middle Ages (c. 1330 – c. 1400). Though born out of wedlock to Sir James "The Black" Douglas, a close ally of King Robert I, Archibald rose to become the 3rd Earl of Douglas. He inherited the title and vast estates after his cousin, James 2nd Earl of Douglas, died childless at the Battle of Otterburn.