It is actually surprisingly simple to narrow down all of the influential books that I have ever read to a single, most life changing one.

You see, this may seem surprising, but up until about 2 years ago, I was a complete vegetarian.  It was a dull life, being a veggie; I’d never been able to experience the full pleasure of a braai, or a succulent burger with everything on it and then some.  I was one of those confused cases of a “moral vegetarian”.  This meant that I didn’t eat meat because I felt sympathy for suffering caused to animals by our evil human actions when they are slaughtered for our taste-buds.  I did not believe that it was morally acceptable to take the life of an animal simply for the enjoyment of eating it. 

Now morality is an immensely strong force.  It is the same force that stops you from stealing the purse of some sweet old granny, or taking candy from a baby.  Morality influences nearly all decisions that you make in your life.  It is therefore an inherently difficult quality to change. However, I read a book that did manage to change my morality.  It is called Do Animals Have Right? and is by Alison Hills.  This book succeeded in convincing me to change one of the cornerstones of what I believed in.  The book does not only give a single-sided view vegetarianism.  Quite the contrary in fact.  Half of the book is devoted to promoting vegetarianism and half is devoted to hinder its plight.  It is unbiased in its outlook, and gives the reader a choice on whether to believe either one of the sides.
The arguments in the anti-vegetarianism side of this book managed to convince that animals suffered in a different way to humans.  By this I mean that the experiences of pain, emotions and self-awareness is less pronounced in animals than in humans, and it is therefore impossible to empathise with them or accurately sympathise.

This realisation has altered a belief that I had held for 15 years.

Pretty life changing hey.