In 1892, Salt wrote a seminal, scholarly book called Animals' Rights Considered in Relation to Social Progress.
In his preface to the 1980 reissue of Animals’ Rights, Peter Singer stated, “Animals' Rights was not the first book to defend the case for the rights of animals, as Salt's own excellent bibliography makes clear... Animals' Rights is, I believe, the best of the eighteenth and nineteenth century works on the rights of animals. Every time I re-read Salt's book - and I have read it several times - I marvel at how he anticipates almost every point discussed in the contemporary debate over animal rights.”
Salt's wise words include: “The emancipation of men from cruelty and injustice will bring with it, in due course, the emancipation of animals also, the two reforms are inseparable, and neither can be fully realised alone.” And in a chapter on “Sport or Amateur Butchery,” he wrote:
“The sports of hunting and coursing are a brutality which could not be tolerated for a day in a state which possessed anything more than the mere name of justice, freedom and enlightenment.”
Animals' Rights was reprinted in 1894 with an “Essay on Vivisection” by Albert Leftingwell as an appendix.
Two subsequent revised editions appeared in 1905 and 1922.
After an interval of over fifty years Animals' Rights was reissued with Singer's preface.