The collection consists mainly of Mansbridge's letters to Leonard Clark. There are also a few manuscripts concerning Mansbridge, Christmas cards, invitations, and announcements relating to Mansbridge, photographs of Mansbridge, and some pamphlets by Mansbridge. This collection was assembled by his friend Leonard Clark. Clark, an educator, author, editor and poet was born on 1 August 1905 in St. Peter Port, Guernsey. He was made inspector of schools with the Ministry of Education in 1936. He died in London in 1981.

The fonds consists of material related to Alan Walker's research, recordings, and other professional activities. As well as personal material, including correspondence. The third accrual contains 30 items related to Liszt and his Circle, including 14 letters from Liszt.