The letters relate to:
Pond Problems by Unwin, E.E.
Greek Sculpture and Painting by Beazley, J.D. and Ashmole, B.
Science and the Modern World by Whitehead, A.N.
Jane Austen by Cecil, D.
A Song of the Ungirt Runners by Sorley, C.H. and two letters from Sorley, K.W.
Studies in Literature by Quiller-Couch, A.
The Eighteen Eighties edited by Mare, W. de la
Adventure of Ideas by Whitehead, A.N.
Din of a Smithy by Stevenson, J.A.R.
Country Relics by Massingham, H.J.
Village Carpenter by Rose, W.
Journal of Anatomy Volume 65.