Four hundred and thirteen family and other letters, [c. 1883]-1963, addressed to Lucy Penny's siblings, comprising: (i) sixty nine letters, 1890-1963, to John Cowper Powys from C. F. Powys (1), 1890, Littleton Powys (1), 1948, William Powys (36), 1943-1954, Lucy Penny (6), 1932-1948, Mary Casey (6), 1942-1954 (with 1 to Phyllis enclosed), Gerard Casey (14), 1944-1954, Frances Gregg (1), [1912x1914], H. E. Fanshawe (1), 1894 (letter of recommendation for JCP as a lecturer), and Frederick E. Davies (1), 1963; (ii) six letters, [c. 1886]-1954, to Littleton C. Powys from Theodore Powys (1), Gertrude Powys (2), Lucy Penny (1), [Hermione Justice Shirley], Countess Ferrers (1), and Patrick Bury (1); (iii) six letters, [c. 1883]-[1945], to Theodore Powys from John Cowper Powys (2), Gertrude Powys (1), Llewelyn Powys (1), Lucy Penny (1) and Mary Casey (1); (iv) one hundred and eighty-seven letters, [c. 1883]-1952, to Gertrude Powys from C. F. Powys (7), 1893-1918, Mary Cowper Powys (23), 1893-1914, John Cowper Powys (5), [c. 1883]-1949, Littleton Powys (2), 1945, Theodore Powys (2), [c. 1886], 1947, Eleanor Powys (1), 1891, Llewelyn Powys (2), 1937, Katie Powys (2), 1951-1952, William Powys (21), [1914]-1950, Lucy Penny (65), 1935-1951, Mary Casey (14), 1930-1950, various other relatives (20), 1913-1949, Alyse Gregory (11), 1939-1952, Phyllis Playter (4), 1939-1951, and Bernard O’Neill (6), 1942-1947; (v) six letters, [c. 1883]-[c. 1893], to Eleanor Powys from John Cowper Powys (3) and Gertrude Powys (3); (vi) six letters, [?1909]-[1915x1936], to Albert Reginald Powys from Katie Powys (1), William Powys (1) and Lucy Penny (4); (vii) three letters, 1893-1949, to Marian Powys from Llewelyn Powys (1) and others; (viii) seven letters, 1910-1936, to Llewelyn Powys mostly from his siblings; (viii) one hundred and four letters, [1880s/1890s]-1962, to Philippa (Katie) Powys from C. F. Powys (1), 1919, John Cowper Powys (2), [1880s/1890s], [c. 1934], Theodore Powys (5), 1901-1950, Gertrude Powys, (15), 1923-1951, Marian Powys (3), 1929-1960, Llewelyn Powys (4), 1937-1938, William Powys (18), [1910]-1962, Lucy Penny (23), 1915-1954, Mary Casey (20), 1943-1962, Phyllis Playter (4), 1954-1962, Alyse Gregory (1), 1962, Bernard O’Neill (3), 1930-1947, Valentine Ackland (1), 1954, and others; and (ix) nineteen letters, 1903-1949, to William Ernest Powys from Gertrude Powys (5), 1935-1949, Llewelyn Powys (8), 1917-1937, Katie Powys (2), [c. 1922], Lucy Penny (2), 1936, Alyse Gregory (1), 1939, and Bernard O’Neill (1), 1903.
The letters of Gertrude Powys and William Powys occasionally contain thumbnail sketches or watercolour drawings.