Books:

A Group of Unpublished Letters by Henry S. Salt to Joseph Ishill Oriole Press, Berkeley Heights, New Jersey 1942
An Examination of Hogg's 'Life of Shelley' Richard Clay & Sons, London, 1889
Consolations of a Faddist, Verses Reprinted from 'The Humanitarian', A. C. Fifield, London, 1906
Eton under Hornby: Some Reminiscences and Reflections A. C. Fifield, London, 1910
Homo Rapiens, and Other Verses Watts & Co., London, 1926, 70 pages
Literae Humaniores, An Appeal to Teachers The Humanitarian League, 1894
Tennyson As a Thinker A criticism
The Case Against Corporal Punishment The Humanitarian League
The Heart of Socialism: Letters to a Public School Man Independent Labour Party, London, 1928
The Humanities of Diet, Some Reasonings and Rhymings
The Life of James Thomson ('B.V')
The New Charter, A Discussion of the Rights of Men and the Rights of Animals George Bell & Sons Ltd., London, 1896
The Nursery of Toryism: Reminiscences and Reflections A. C. Fifield, London, 1911
 

Salt Essays:

Shelley's Gospel of Nature The Hygienic Review, No. 19, July 1, 1892, pages 185-187
Can the Social Residuum be Stamped Out? Progressive Review, Vol. 1, No. 5, (Feb 1897), p. 461 (Google Book Search)
Confessions of an Eton Master The Nineteenth Century, XVII January 1885 (Source 3, page 23 Ref.31)
Herman Melville The Universal Review, IV, 78 (May, 1889)
Imperial Cockneydom, The Scottish Art Review, II, 186-190 (November, 1889)
Nature Lessons from George Meredith The Free Review, September 1896, Vol. IV., p. 502 (Google Book Search)
Socialists and Vegetarians To-day, November 1886, pages 172-74 (Source 3, page 50)
? (unknown title on Socialism) The New Nation's, 12 December 1891 (Google Book Search)
Thoreau Hygienic Review, May 1896 (Source 3, page 110)
Thoreau Temple Bar, November 1886 (Source 3, page 99)
Thoreau's Life The Spectator, No. 65 - October 18, 1890, pages 526-527 (Source 3, page 103)
Walking Stewart Temple Bar, December 1891, 93: 573-578 (Source 1)
 

Poems:

The Joy That Never Palls Progress, VI, November 1886, page 456 (Source 3, page 23 Ref.22)
 

Reviews:

Salt and His Circle by John Davies, Vegetarian Messenger, No date - 1951? (Source 3, page 6 Ref.1)
Life of Thoreau, Animal World (a journal of the RSPCA), November or December 1890 (Source 1)
 

Articles or other sources of information on Salt:

Henry S. Salt, the late Victorian Socialists, and Thoreau, New England Quarterly, 1977, pages 409-22 (Source 2)
The Labour Annual for 1897 (Source 2)
Edward Carpenter 1844-1929: Prophet of Human Fellowship by Chushichi Tsuzuki (Cambridge, 1980) 0-52123-371-2 (Source 2)
The Books of Henry S. Salt, 1887-1937 by Raymond Adams (Source 3) Online Version
Literary Comments in the Letters of Henry S. Salt to W.S. Kennedy by George Hendrick (Source 3)

RESEARCHER INFORMATION

Salt's Letter can be found:

The Fabrian Archive, Nuffield College, Oxford
Edward Carpenter Collection, Sheffield City Library (website) also see (A2A listing)
G. B. Shaw Papers, British Library
George Bernard Shaw, Papers, 1879-1937 at Kent State University Libraries
John Galsworthy Letters, Syracuse University Library - Seven letters written between 1909 and 1910 to Salt
George Meredith Letters, University of London - Letters to Salt
Alfred Russel Wallace Collection - Two letters to Salt
George Bernard Shaw Collection, Harry Ransom Centre - Salt and S. Winsten
Alfred Winslow Hosmer Collection - Salt Letters

Collections of Salt Material can be found at:

Thoreau Institute (website)
Working Class Movement Library (website)
Northwestern University (website)
University of Oxford, Bodleian Library (website)
 

Sources of information:

1. Henry Salt and His Life of Thoreau by John T. Flanagan, The New England Quarterly 28, June 1955, pages 237-246
2. Salt, Henry Shakespear Stephens (1851-1939) by David E. Martin, Biographical Dictionary of Modern British Radicals Volume 3, 1870-1914, L-Z
3. Henry Salt, Humanitarian Reformer and Man of Letters, by George Hendrick
4. Walter Harding Collection: A Finding Aid
5. Brigid Brophy's review of Salt's Animals' Rights, TLS, 16 January 1981, page 48

Bernard Shaw: Collected Letters, edited by Dan H. Laurence (London, 1965-72), 2 volumes (Source 2)
(Vol.1: 1874-97, Vol. 2: 1898-1910, Vol. 3: 1911-1925, Vol. 4: 1926-1950)
The First Fabians by Norman & Jeanne MacKenzie (New York, 1977) ISBN 0-297-77090-X. (Source 2)
The Genuis of Shaw by Michael Holroyd, Hodder and Stoughton, London, 1979. 238pp (Source 5) - (Incudes a photograph of Salt)
Life and Letters of John Galsworthy by H.V. Marrot. (Charles Scribner’s Sons, 1936, 819 pages)