Science and religion have frequently been pictured as antagonistic, but talking to scientists about their faith reveals a wide range of views and a much more complex picture. For some scientists there is a clear divide between science and religion, and they view them as separate domains that should be kept apart from each other. Others have a strong faith and are confident that this has been integral to their work, which has been guided at crucial moments by an external power. Some scientists with a strong faith have found themselves moving into research areas where their religious beliefs and scientific work do not come into conflict. For some interviewees, training as a scientist called into question existing beliefs, prompting a process of self-examination and reflection from which new understandingsand a firmer commitment emerged. In other cases studying science led to a rejection of religion, which came to be seen as incompatible with being a scientist. These scientists seem uncomfortable with the idea of beliefs that are not based firmly on evidence and cannot be tested.