Ordinary mental activities such as recognizing a word, forgetting a phone number, and distinguishing a cup from a glass seem transparently simple. Examined more closely, they are complex and not easily explained. Cognitive psychology is the empirical study of longstanding questions about what we know, how we know it, and how our knowledge is structured, accessed, and used. We start with the psychology of William James, which examines how we experience thought and feeling. With that background, we examine the theory, research, and methods of contemporary cognitive psychology. We consider attention, perception, memory, the structure of knowledge, language, reasoning, problem-solving, and cognitive neuroscience.