Miles Davis used to tell his musicians: “Don’t play what’s there. Play what’s not there.” In other word, pay attention to the space in between the notes. In similar concept, Cyrus Highsmith advises designers to look at the typographic space (such as glyph, counter, letter and line) rather than the text in a paragraph. The purpose is to understand what’s happening behind the scenes when setting body copy. It’s a great little book to have for quick reference.