Did you know that the Merck Veterinary Manual is available in its entirety online? For more information that you could ever absorb, take a look: http://www.merckvetmanual.com/mvm/index.jsp. It’s the self-described “World’s Most Trusted Veterinary Reference,” now in its 19th printing, with detailed information on emergency care, nutrition, diseases, behavior, reproduction, etc. There’s a handy index, so you can search and sort by species (unless you really want to read about Pseudopregnancy in Goats).
Whether you want to learn more about canine cancer or brush up on the immune or circulatory system, this is a meaty volume written for professionals. If you’re not a veterinarian, this is probably “inside baseball” stuff. But I thought it was so cool.