Neuro-ophthalmology is about getting a good history. The best history is obtained by knowing the general principles of neuro-ophthalmology, applying critical aspects of anatomy and physiology, and having a clear understanding of the differential diagnosis. This differential diagnosis begins broadly and proceeds to the narrow based on answers to the questions posed. An example is given in the case of a 68-year-old woman with painless loss of vision that came on over several months.