This book bridges the gap between religious and secular, to present a well-reasoned set of arguments for why vegetarianism is the best form of kashrut today. The author does not condemn previous generations for eating meat, and is respectful of the kosher slaughtering process (shechitah) as it was practiced for many generations. However, she also feels that, in the light of the cruelty of modern factory farms, it is no longer enough to focus only on the moment of slaughter. Shechitah itself is humane, but the ways in which the animals are raised and transported to the meat processing plant are not. Kosher and non-kosher meat come from the same commercial sources, and the animals are all raised the same way. "The distinction between kosher and non-kosher meat, "she writes, "is made at the ramp to the slaughtering house."
In chapter 2, "From living soul to animal machine," Kalechofsky traces the philosophical developments that have led to the Western acceptance of the cruelties of modern factory farms. Most enlightening to me was the section discussing the influence of the (gentile) French philosopher, Renee Descartes. Best known for "I think, therefore I am," Descarte also thought than animals were like machines (automata) and do not feel pain or emotional stress. As a mathematician, Descartes saw everything in terms of what could be counted and measured in the physical world. Subjective experiences such as animal suffering were, to him, of no account whatsoever.
This chapter was an eye-opener for me, because I had not studied Descarte's philosophy in any depth before. As far as I knew, he played no role whatsoever in Jewish life. Wrong. Although most religious Jews do not study Descartes, the civilization we live in has been strongly influenced by him. When it comes to animals, many Jews are de facto Cartesians, even if they have never heard of Descartes.
Kalechofsky traces the line from Descartes to factory farms, which tend to regard animals as little more than egg-milk-meat producing machines. She also cites references to demonstrate that this attitude is NOT acceptable in classical Jewish thought. "Either animals are part of God's creation or they are not," she writes, "and if not, Genesis is false. The antithesis, foreseen in the 17th century, has come to its final crisis: You cannot support the Cartesian view of animal life and the biblical view at the same time." (Page 35)
Because the kosher food industry is so firmly emmeshed in the modern factory farm system, it is next to impossible to find kosher meat from animals that have not been badly mistreated in the name of "progress." That alone should lead a sensitive Jew to give up eating meat. But there are other reasons, too -- reasons of health, economics, and social responsibility. These the author fully explores. She also points out that a vegetarian diet bridges the gap between Jews who keep kosher and those who don't. Many synagogues and other Jewish organizations have begun serving vegetarian meals for precisely this reason. If the purpose of kashrut is to respect life and unite the Jewish people, then vegetarianism is the best way to do this in the 21st century.
I also recommend Judaism and Vegetarianism by Richard. H. Schwartz, which traces the biblical and rabbinical basis for Jewish vegetarianism, and has an excellent FAQ section.