How deep are the bounds on human thinking and feeling and how do they shape social judgment? To answer this question, I have chosen to investigate systems that operate in implicit or unconscious mode, with a focus on implicit assessments of self, other humans, and social groups. In this talk I will show evidence for the existence of implicit attitudes and knowledge, and what we know so far about their nature. With evidence from measures of conscious and less conscious social cognition, with techniques that access behavior and brain, with participants who are college students and visitors to the world wide web, I will raise some questions of interest to psychological theory, methodological innovation, and what the mind sciences can contribute to understanding the early mental threats to just treatment.