Arousal is fundamental to all cognition. It is intuitively obvious, absolutely necessary, but what exactly is it? In Brain Arousal and Information Theory, Donald Pfaff presents a daring perspective on this long-standing puzzle. Pfaff argues that, beneath our mental functions and emotional dispositions, a primitive neuronal system governs arousal. Employing the simple but powerful framework of information theory, Pfaff revolutionizes our...