Because of the diversity and complexity of deaf-blindness, the task of assessment is "best approached with the mindset that you are engaged in a process of discovery" (Rowland, 2009). It incorporates a variety of methods including observation, interviews with people who know a child well, evaluations by specialists, and direct interactions. This broad range of assessment activities takes considerable time, planning, and effort, but is achievable and essential in order to gather useful information about what a child knows, how they demonstrate what they know, and how they learn. This NCDB Practice Guide shares essential components of a high-quality assessment of children who are deaf-blind.