I have Radical Vegetarianism by Mark Matthew Braunstein. The dietary chapters are very biased towards raw Buddhist/yogi veganism which is a bit tiring but the ethics chapters are BRILLIANT ...there are three chapters in the book that are extremely rationally argued and in context of historical sociology in the United States. It was published in 1981 and it gave me real insight into just how long people have known about the environmental risks and factory farm cruelty - a lot of what he said is still so relevant that its actually disturbing that veganism took this many decades to catch on. The author had been vegan since 1970. No wonder straight edge punk vegans were burning down buildings in the 80s - people were even more blind then than they are now.
I also have Do Unto Animals by Tracey Stewart which is practical tips for caring for different species of animals.
I have Love for Animals Large and Small by Ingrid Newkirk which I think is free to all paying PETA members.
I have PawPrints on Our Souls by S. Francis which is a collection of vegan, vegetarian and animal rights quotes punctuated by the grisliest accounts of animal testing and other ethical/bearing witness input. Its very rare as well as being odd. There's literally one copy on Amazon priced 52 dollars. I got mine at a used book store for maybe 10.
I want to order The Books of Enoch. Its Jewish texts that were removed from the Christian Bible which state meat eating is demon-inspired and unnatural. What a treasure to be able to share with all the "but God said animals are for me" idiots in your life.
I should probably read more serious vegan literature but I get most things in online versions or on videos.
I went out and bought Peter Singer's Animal Liberation today as a result of this conversation so thanks for bringing it up. If you do watch on-line videos, check out Bite Size Vegan = Emily Moran Barwick. She has three videos on Veganism in Antiquity, the Middle Ages and the Renaissance. Emily has a lot of good material but those three are on a different level.
Currently reading a cookbook called "Veganomicon" for the recipes, which have been quite fun to try out. Will be picking out a few vegan philosophy books once I'm done exhausting those cooking tryouts, as otherwise I've only really touched the surface reading the odd essay/article every now and then.
I did recently re-read Animal Farm by George Orwell. Among other things it is very much laced with the unthinking cruelties humans perpetuate against animals. Regarding the classic, going vegan gave me a few more things to think about by the end.