One quick way to assess one’s proficiency in a chosen field is to pick up an advanced undergrad level or a beginning grad level #textbook on a foundational subject of the field and to confirm that (1) one fully grasps, not merely be acquainted with, all titles and subtitles in the table of contents; (2) one is aware of how these concepts relate to each other as well as to the subject as a whole; and (3) one is additionally aware of the subject’s foundational nature of the field.