Gohebiaeth bersonol Robert (Silyn) Roberts oddieithr rhyngddo ef a'i wraig, Mary Silyn Roberts, y gohebwyr yn cynnwys Jane Parry ac Evan Parry, mam a brawd Mary Silyn Roberts; y bardd a'r ysgolhaig W. J. Gruffydd; a chasgliad pwysig o lythyrau o'i gyfnod yn y Rhyfel Byd Cyntaf oddi wrth y bardd R. Williams Parry. = Personal correspondence of Robert (Silyn) Roberts other than that between him and his wife, Mary Silyn Roberts, the correspondents including Jane Parry and Evan Parry, mother and brother of Mary Silyn Roberts; the poet and academic W. J. Gruffydd; and an important collection of First World War letters from the poet R. Williams Parry.