In this book the author discusses a historic theory of emotion in the context of his own research and ideas. According to the theory, known as the James-Lang theory of emotion, our emotions derive from the perception of our body's response to an emotionally charged stimulus. The classical argument ran as follows. We see a bear and our heart starts to beat fast, our breathing becomes shallow and fast and we run away, we then feel fear. The other theory of emotion; dismissed by the author of this book, agues the opposite. We see the bear, feel fear, and then have then our body reacts. In the book Damasio presents some convincing evidence for the James-Lang theory of emotion. He makes a distinction between emotions on the one hand and feelings on the other. He defines emotions as the person's response to some emotional situation that can be observed by an outsider, and feelings as the person's subjective reaction that cannot be seen by an outsider. He then goes on to argue that feelings are the perception of our body's responses to internal and external stimuli. We feel happy when we are balanced physiologically. We feel frightened when our body shows a physiological response to, say the bear. The evidence that he presents comes mostly from his own research, and it is convincing. He expands on the theory, arguing that feelings play an important role in our lives, that they enable us to interact with others smoothly and that they are crucial for decision making. Here he draws his evidence from his work with his patients who have suffered brain damage to specific brain regions. I bought this book because I enjoyed his book 'Dascartes Error' so much. However, I found 'Looking for Spinoza' long-winded in parts and sometimes boring. The sections devoted to Damasio's own research were very interesting, though I suspect one would have to have a background knowledge of brain and behaviour to fully appreciate them. He mentions brain regions as if he is discussing the pub next door with a neighbour. I also had difficulties in seeing the relevance of Spinoza to his arguments, and the penultimate chapter body brain and mind was frankly dull.