SERIES I: HORNE LETTERS, 1891-1912
Correspondence from Horne to Douglas Ainslie, 1912
Correspondence from Horne to Thomas Cobden-Sanderson, 1891
Correspondence from Horne to Edgar Jepson, 1896-1900
Transcriptions of Jepson correspondence, 1896-1900
Correspondence from Horne to Sarah Prideaux, 1899-1903
Transcriptions of Prideaux correspondence, 1899-1903
Correspondence from Horne to Gleeson White, 1892
SERIES II: HORNE DRAWINGS, 1899-1903
Horne's artwork and proofs for Prideaux's The Elements of Architecture, 1899-1903
SERIES III: OTHER LETTERS, 1894-1942
Correspondence from Dudley Harbron to Edward Carter, 1942
Correspondence from Selwyn Image to Edgar Jepson, 1894
Correspondence from A.H. Mackmurdo to Dudley Harbron, 1936
Correspondence from D.B. Updike to Lloyd Stanford, 1925-1926
SERIES IV: MISCELLANY, 1886-1973, N.D.
Biographical and other velated material, 1886-1973, n.d.