I just finished a very good book: Beyond Words - What Animals Think and Feel by Carl Safina. If you like animals, then you will really enjoy this book. It's long, but you don't notice it. The audiobook is 16 hours on 2 mp3 CDs.
Carl spends large portions of the book describing his experiences working with animal researchers observing elephants in Kenya, wolves in Yellowstone National Park, and killer whales near Seattle. With ease, he presents compelling arguments about various animals' intelligence and emotions. Along the way he describes the application of the observed animal behaviors and theories to dogs, chimps, bonobos, dolphins, foxes, scrub jays, hawks, bats, and more.
The book criticizes and ridicules scientific researchers for their puzzling, and sometimes obviously inaccurate, findings. There's a decent description of the Theory of Mind and how it applies to animals. Carl presents several examples of how animal researchers have it wrong; how they are misinterpretting their own observations; and how their own published papers are not even self-consistent on the topic. He does the same with researchers' misinterpretation of mirror mark tests.
This book does a great job of explaining how animals think, plan, teach, reward, deceive, mourn, play, and more with far more complex and richer social lives than most people realize. Carl shows that many animals possess attributes traditionally associated with humans and not with other animals: consciousness, intelligence, rationality, creativity, empathy, love, self awareness, and compassion.
Some would argue that Carl does this through the anthropomorphising lens of human experience, and that this is unscientific and propagates bias that leads to false assumptions and false findings. Carl does a decent job of explaining how this perspective is, indeed, acceptable and this is how humans begin to understand the world around them. To do otherwise will dramatically slow the acquisition of knowledge.
The book is not crammed with clinical jargon. In fact, the style is very conversational and easy to understand. I enjoyed the book and I highly recommend it.