Start with high-confidence small animal medicine books, then narrow by subgenre or adjacent topics.
Keep Your Cat Healthy the Natural Way
Pat Lazarus
Decoding Your Dog
Amer. Coll. of Veterinary Behaviorists, Debra F. Horwitz
Pets and the City
Dr. Amy Attas
Home-prepared Dog and Cat Diets
Patricia A. Schenck
Handbook of Applied Dog Behavior and Training, Etiology and Assessment of Behavior Problems
Steve Lindsay
The Spirit of Animal Healing
Marty Goldstein
Healing Touch for Cats
Dr. Michael W. Fox