| A Victorian historian : private letters of W.E.H. Lecky, 1859-78 | | Monograph or Collective Volume | | 1947 |
| A Victorian historian : private letters of W.E.H. Lecky, 1859-78 | Hyde, Harford MontgomeryLecky, William Edward Hartpole, 1838-1903 | Monograph or Collective Volume | Home & Van Thal | 1947 |
| Carson : the life of Sir Edward Carson, Lord Carson of Duncairn | Hyde, Harford Montgomery | Monograph or Collective Volume | Heinemann | 1953 |
| Cases that changed the law | Hyde, Harford Montgomery | Monograph or Collective Volume | Heinemann|Roy | 1951 |
| Mount Stewart, Co. Down | Hyde, Harford MontgomeryJackson-Stops, Gervase | Monograph or Collective Volume | National Trust | 1978 |
| Oscar Wilde : a biography | Hyde, Harford Montgomery | Monograph or Collective Volume | Eyre Methuen | 1976 |
| Oscar Wilde : a biography | Hyde, Harford Montgomery | Monograph or Collective Volume | Eyre Methuen | 1982 |
| The Irish and Catholic power : an American interpretation | Blanshard, PaulHyde, Harford Montgomery | Monograph or Collective Volume | Verschoyle | 1954 |
| The Londonderrys : a family portrait | Hyde, Harford Montgomery | Monograph or Collective Volume | Hamish Hamilton | 1979 |
| The rise of Castlereagh | Hyde, Harford Montgomery | Monograph or Collective Volume | | 1933 |
| The Russian journals of Martha and Catherine Wilmot. Being an account by two Irish ladies of their adventures in Russia as guests of the celebrated Princess Daschkaw, containing vivid descriptions of contemporary court life and society, and lively anecdotes of many interesting historical characters, 1803-1808 | Hyde, Harford MontgomeryVane-Tempest-Stewart, Edith Helen, marchioness of Londonderry, 1878-Wilmot, CatherineWilmot, Martha | Monograph or Collective Volume | | 1934 |
| Their good names : twelve cases of libel and slander with some introductory reflections on the law | Hyde, Harford Montgomery | Monograph or Collective Volume | Hamilton | 1970 |
| Trial of Sir Roger Casement | | Monograph or Collective Volume | William Hodge | 1960 |
| United in Crime | Hyde, Harford Montgomery | Monograph or Collective Volume | William Heinemann | 1955 |
| When George IV visited Ireland | Hyde, Harford Montgomery | Article in Journal | | 1937 |