Ostension is bodily movement that manifests our engagement with things, whether we wish it to or not. Gestures, glances, facial expressions: all betray our interest in something. Ostension enables our first word learning, providing infants with a prelinguistic way to grasp the meaning of words. Ostension is philosophically puzzling; it cuts across domains seemingly unbridgeable—public–private, inner–outer, mind–body. In this book, Chad Engelland offers a philosophical investigation of ostension and its role in word learning by infants.