Tad Williams is a well-known fantasy author, but my favorite of his catalogue is his first novel, the strange, complex cat story Tailchaser's Song. Williams is channeling Tolkien here, inventing an entire world, language, folklore, and layered history, but he's doing it with cats. His feline protagonists are intelligent, self-aware creatures, considering themselves as the primary species on the planet and the center of the universe (as cats are wont to do). These are feral cats, not house cats, and they harbor a certain disdain and disquiet for their unnatural, odd-smelling, domesticated brethren, and a hearty fear of the furless M'an.
The story centers on Fritti Tailchaser, a curious and brave young tomcat who gets caught up in a larger narrative as he seeks to find his lost mate Hushpad. One of the strengths of this novel, aside from the construction of an entire worldview for cats, is the roster of wonderful names Williams has concocted for his characters. One of my personal favorites is Eatbugs, the mad cat, but a quick glance at the appendix gives us Bandyleg, Pouncequick, and Volenibble.
This is above all an adventure story, and Tailchaser a hero. It is mythic, epic, and engaging. I loved it at 10, though much of it was beyond me. I very much need to read it again.