Don't Panic by Reid Wilson is the best book for people who suffer from panic attacks. In addition to a cognitive-behavioral approach, it addresses changing the biological aspects of a panic attack. Apparently, the attacks are a physiological response to chronic hyperventilation, shallow, rapid breathing that leads to the fight or flight response. The author of this book, Reid Wilson instructs the reader in how to change to deep diaphragmatic breathing, slowly and steadily, so that oxygen-carbon dioxide exchanges are altered and corrected. The one and only chapter on breathing is the single most powerful intervention I've found for this disorder.