In Roman times, blocks of text were written without even wordspacingnevermindpunctuation. Orators would prepare carefully so that they didn’t get confused between, say, therapists and the rapists. As we entered the Christian era, it became more important to remove any likelihood of misinterpretation. For example, "If you are tempted, yield not, resisting the urge to commit a sin" vs. "If you are tempted, yield, not resisting the urge to commit a sin." So yes, punctuation does matter, and it is there to help—to clarify meaning, to convey emphasis, to indicate that you are asking a question or quoting someone else’s words. Caroline Taggart points out what matters and what doesn’t; why using six exclamation marks where one will do is fine in a text but not at school; why hang glider pilots in training really need a hyphen; and how throwing in the odd semicolon will impress your friends. This is an ideal guide to the (perceived) minefield that is punctuation.