For over four decades, there have been efforts to specify the types of knowledge that medical students need, how that knowledge is acquired and how its constituent parts are related. It is one of the areas of continuing concern underlying medical education reform. Despite their importance to medical students' learning and development, the perspectives of medical teachers in hospitals are not always considered in such discourse. This study sought to generate an understanding of these teachers' values, perspectives and approaches by listening to them and seeing them in their everyday teaching work, finding and understanding the meanings they bring to the work of medical teaching in hospitals. In interviews, all of the teachers talked more about the optimal forms of knowledge that are important for students than they talked about the form of the teaching itself. Many revealed to students what knowledge they do and do not value. They had a particular way of thinking about clinical knowledge as existing in the people and the places in which the teaching and the clinical practice happen, and represented this as "real" knowledge. By implication, there is other knowledge in medical education or in students' heads that is not real and needs to be transformed. Their values, practices and passions add texture and vitality to existing ways of thinking about the characteristics of clinical knowledge, how it is depicted in the discourse and the curriculum and how it is more dynamically related to other knowledge than is suggested in traditional conceptualizations of knowledge relationships.