Few books have the power to disgust their readers or send them racing to remove foodstuffs from their refrigerators. Written originally in 1975, Animal Liberation is part vegetarian ethical manual, part meat-bashing, part research and all moral righteousness. Author Peter Singer understands the reluctance of meat-eating Europeans to give up their "normal" diet. Except for extremely sensitive animal-lovers who from birth seemed to understand that animals were equal – no better, no worse – than humans, the rest of the world loves animals and are inclined to ignore animals or their pain at dinnertime. Knowing this, Singer writes a book which uses those elements most likely to turn his readers against "speciesism": research into lab experiments, descriptions of the heartlessness and uncleanliness of the factory system, appeals against Christianity (which he blames for the world's meat-eating habit), cultural institutions and media biases, and other objections to speciesism.

The book is exhaustively researched. Singer tells his readers that this book – his appeal for animal liberation - is a rational and moral appeal and not an appeal based on "good-heartedness" or sympathy. For the most part, this is true. Every aspect of meat-eating is explored. For instance, in the section on factory farming, he brings in, among other things, abuse and mistreatment, economics (small farms who are dying at the hand of large corporations), communal animal self-destructiveness and countless stresses caused by human greed. The large bibliography at the back is proof of Singer's diligent research. But the description of trapped birds painfully flapping their wings against wired cages and the horror of bored pigs certainly works on the reader's emotions. Could any human mother read Singer's passages about sows (perpetual reproductive machines) losing their piglets without getting choked up with grief about the harrowing scene?

All this research did not become suspect until I reached the section called "Man's Dominion." Singer's treatment of Judaism and Christianity as the base cause of the entire world's meat-eating habit is so feral and one-sided that it makes the reader wonder if the rest of the information given in the other areas of the book might not be as unbalanced. For instance he writes,

"...there is no serious challenge to the overall view, laid down in Genesis, that the human species is the pinnacle of creation and has God's permission to kill and eat other animals."

"Christianity spread the idea that every human life – and only human life – is sacred... The New Testament is completely lacking in any injunction against cruelty to animals, or recommendation to consider their interests."

Thus, Singer completely ignores the obvious: the beginnings of Christianity were times of turmoil and persecution and its adherents hardly had the time or the power to discuss theoretical ethics when their lives were in danger. He conveniently ignores the ramifications of many of his theories. For instance, he mentions Darwin's theory that humans were descended from non-human animals, but he doesn't comment on the fact that the survival of the fittest certainly made some animals carnivorous and created the "food chain." It is the wrong-doings of humans that concern him.

Throughout, Singer equates speciesism with racism and uses concentration camp analogies when he speaks of caged animals, arguments which might offend those ethnic groups who have had to endure lynchings or torture in their histories. In this respect, the book is slightly offensive in many sections, especially for those readers or human sufferers who might consider animal liberation not terribly important. This, in addition to the idea that animal liberation is a "topic" to be discussed in academia, can also reinforces the point that animal liberation could be viewed by some people as merely a toy issue, not a real one.

And yet, Animal Liberation is one of the best books on animal rights, vegetarianism and vegetarian spirituality. Its historical, economic and political research are valuable, although the writer's blatant agenda loses some of its speed for those who might feel his treatment of the topic is a bit unbalanced. The writing is passionate, as befits a topic the author clearly feels passionate about.