The book came from the family library of Hubert Priestley who was a famous botanist in the 1930s and brother to the Antarctic explorer and geologist, Sir Raymond Edward Priestley.
Priestley had strong connections to the University of Oxford where Tolkien stood as Rawlinson and Bosworth Professor of Anglo-Saxon and a Fellow of Pembroke College.
Both men knew fellow author C.S. Lewis and it is likely that they knew each other.
“It’s the connection to Tolkien and the important provenance that makes this book so special. It’s not just any first edition; it belonged to someone who very likely called Tolkien an acquaintance,” Ms Riley said.
She added it was astonishingly rare to find a first edition in such good condition.
“Being a children’s book, most of them have seen children’s hands, children’s colouring pens in some cases, so to have one that appears to be completely unread and never enjoyed is really, really astonishingly rare,” she said.