Thought, in a sense, transforms the world. When we think of a particular thing - Charlie the dog, for example - we always think of it in a universal way: as a dog. Through this act of thinking, Charlie comes to exist in our mind and becomes the dog that is the object of our thought. Explaining how our act of thinking relates to and transforms the reality around us is often considered the hallmark of the modern age. Yet the Middle Ages offer illuminating examples of speculation on the human mind and how it functions. This book explores the views on mental acts, concepts and objects of the mind of two of the most eminent Dominican authors of the late Middle Ages: Thomas Aquinas and Hervé de Nédéllec, one of his closest followers. By putting Aquinas and Hervaeus Natalis directly in conversation with each other Amerini proposes a new interpretative framework for understanding their philosophy of mind and traces the origins of modern accounts of the intentionality of the mind.