A significant work by J.R.R. Tolkien on Chaucer sat unnoticed in a library basement for 60 years. “Tolkien’s Lost Chaucer” tells the story.
“Chaucer: A European Life” by Marion Turner is a significant work of scholarship on the context of the life of Geoffrey Chaucer.
“The Canterbury Tales” by Geoffrey Chaucer wasn’t the first poem in English, but it was the one to mark English becoming the official language of Britain.