The volumes consist of manuscripts compiled by John Gray, minister of Aberlady (who bequeathed his library and a sum of money to the town of Haddington) (MSS 16446-16467), other manuscript volumes written by Gray and by others, which were certainly or possibly in his possession (MSS 16468-16478), and volumes containing records of the Gray Library 1732-1885 (MSS.16479-16482).

Printed labels identifying the volumes as manuscripts were pasted to the spines of most of them apparently in the eighteenth or early nineteenth century.