Echo what Chris posted. A very lucky find. Aberdeen University Special Collections would be very interested.

Not quite the same league but in Edinburgh I picked up Chappell's personal copy of Vol 1 of his Popular Music of the Olden Time.

WW was 1840-1931. He helped Child a lot in the years before Child died, (1882-98) by arranging for Child to get hold of manuscript collections. He also helped Child with his glossary of Scottish words and topographical issues. Then when Greig came on the scene he influenced Greig's attitude to Buchan's ballads and sent items for inclusion in the collection (1914-1920), then after Greig died he influenced Keith to publish the Child ballads that Greig had collected (Last Leaves 1925). He also wrote the biography of PB.