"...it is ourselves, our own vital instincts, that we wrong, when we trample on the rights of the fellow-beings, human or animal, over whom we chance to hold jurisdiction."

Henry Stephens Salt  was a noted ethical vegetarian, socialist, humanitarian and pacifist. It was Salt who influenced Gandhi's study of vegetarianism and non-violent protest. He is credited with being the first writer to argue explicitly in favour of animal rights. He was way ahead of his time in his approach to animal welfare. 
Henry Salt is indeed an interesting turn-of-the-century writer whose ideas have been greatly influential and whose books are still worth reading.
Salt believed animals should be free to live their own lives and that humanity has a responsibility to treat them compassionately and justly. 

CONTENTS :
Prefatory Note 
Chapter I - The Principle of Animals’ Rights
Chapter II - The Case of Domestic Animals
Chapter III - The Case of Wild Animals
Chapter IV - The Slaughter of Animals for Food
Chapter V - Sport, or Amateur Butchery
Chapter VI - Murderous Millinery
Chapter VII - Experimental Torture
Chapter VIII - Lines of Reform
Appendix- Bibliography of the Rights of Animals

Excerpt: «The object of the following essay is to set the principle of animals' rights on a consistent and intelligible footing, to show that this principle underlies the various efforts of humanitarian reformers, and to make a clearance of the comfortable fallacies which the apologists of the present system have industriously accumulated. While not hesitating to speak strongly when occasion demanded, I have tried to avoid the tone of irrelevant recrimination so common in these controversies, and thus to give more unmistakable emphasis to the vital points at issue. We have to decide, not whether the practice of fox-hunting, for example, is more, or less, cruel than vivisection, but whether all practices which inflict unnecessary pain on sentient beings are not incompatible with the higher instincts of humanity.
I am aware that many of my contentions will appear very ridiculous to those who view the subject from a contrary standpoint, and regard the lower animals as created solely for the pleasure and advantage of man; on the other hand, I have myself derived an unfailing fund of amusement from a rather extensive study of our adversaries' reasoning. It is a conflict of opinion, wherein in time alone can adjudicate: but already there are not a few signs that the laugh will rest ultimately with the humanitarians.
My thanks are due to several friends who have helped me in the preparation of this book; I may mention Mr. Ernest Bell, Mr. Kenneth Romanes, and Mr. W. E. A. Axon. My many obligations to previous writers are acknowledged in the foot-notes and appendices.»