Observing lessons and giving feedback are fundamental aspects of mentoring which offer exciting opportunities for intellectually stimulating, enriching dialogue through which beginning teachers and mentors can be challenged and grow in their professional practice. These dialogues happen through spoken conversation and written word, and this chapter focusses on the latter by drawing on recent research that is giving increasing attention to the written accounts and their potential for contributing to critical and expansive dialogue about the subject, and educational research. Foregrounding geographical understandings of observation through ideas about positionality and gaze and applying a situated and tentative approach towards knowledge have implications for the ways in which we might engage with lesson observations and feedback. This chapter applies these theoretical insights, draws on recent empirical work, and makes practical suggestions for increasing the ways in which mentors might make evidence and claims more explicit so that beginning teachers become increasingly empowered to critically engage with and use a wide range of evidence in their professional growth.