Design patents and utility patents share a word and almost nothing else. A utility patent claims how an invention works under 35 U.S.C. § 101; a design patent claims how an article of manufacture looks under 35 U.S.C. § 171. This guide compares the two instruments across term, claim structure, examination, cost, the infringement standard, and—most consequentially—the damages a prevailing owner can collect, including the total-profit remedy of § 289 that produced the nine-figure verdict in Samsung v. Apple. It works through the ordinary observer test of Egyptian Goddess, the article-of-manufacture question, the functionality defense, and the 2024 en banc LKQ decision that rewrote design-patent obviousness. It closes with a decision framework and worked hypotheticals for filing one patent, the other, or both, written for judges, practitioners, and inventors alike.