Authors: R. (sorted by quantity of books)
- Eucken, Rudolf 1846-1926 8 books
- Proctor, Richard A. (Richard Anthony) 1837-1888 8 books
- Harding, A. R. (Arthur Robert) 1871-1930 8 books
- Moncrieff, A. R. Hope (Ascott Robert Hope) 1846-1927 8 books
- Eberle, Joseph 1926-2006 8 books
- Johnson, R. Brimley (Reginald Brimley) 1867-1932 8 books
- Lenz, Jakob Michael Reinhold 1751-1792 8 books
- Smith, Richard Rein 1930- 8 books
- Cunninghame Graham, R. B. (Robert Bontine) 1852-1936 7 books
- Coleridge, Christabel R. (Christabel Rose) 1843-1921 7 books
- Bird, Robert Montgomery 1806-1854 7 books
- Cruikshank, Robert 1789-1856 7 books
- Chandler, Joseph R. (Joseph Ripley) 1792-1880 7 books
- Lethaby, W. R. (William Richard) 1857-1931 6 books
- Peary, Robert E. (Robert Edwin) 1856-1920 6 books
- Spears, John Randolph 1850-1936 6 books
- Malthus, T. R. (Thomas Robert) 1766-1834 6 books
- Streatfeild, R. A. (Richard Alexander) 1866-1919 6 books
- Kelson, Keith R. - 6 books
- Gilbert, Robert E. 1924-1993 6 books
- Alger, William Rounseville 1822-1905 6 books
- Sheridan, Richard Brinsley 1751-1816 6 books
- Griswold, Rufus W. (Rufus Wilmot) 1815-1857 6 books
- Sharp, R. Farquharson (Robert Farquharson) 1864-1945 6 books
- Dana, Richard Henry 1815-1882 6 books