Full disclosure: I know the author.
Even though I was already vegan when I read this book, it really opened my eyes to a lot of issues. First and foremost I found the chapters on conservationism and wild animal suffering the most important and eye-opening! It became SO clear that even as a vegan, I and other vegans I know, are still speciesist and engage in speciesist language, behaviour and mindsets.
This book provides the most crucial arguments against speciesism and I find that it is well written. To me it was inspiring in a way that made me want to do even better as an advocate for nonhuman animals and anti-speciesism, I think it's true to say that it changed my life a bit.