“Gaslighting” is suddenly in everyone’s vocabulary. It’s written about, talked about, tweeted about, even sung about (in “Gaslighting” by The Chicks). It’s become shorthand for being manipulated by someone who insists that up is down, hot is cold, dark is light—someone who isn’t just lying about such things, but trying to drive you crazy. The term has its origins in a 1944 film in which a husband does exactly that to his wife, his crazy-making efforts symbolized by the rise and fall of the gaslights in their home. In this timely and provocative book, Kate Abramson examines gaslighting from a philosophical perspective, investigating it as a distinctive moral phenomenon. Gaslighting, Abramson writes, is best understood as a form of interpersonal interaction, a particular way of fundamentally undermining someone. The gaslighter, Abramson argues, aims to make his target experience herself as incapable of reasoning, perceiving, or reacting in ways that would allow her to form appropriate beliefs, perceptions, or emotions in the first place. He seeks not only to induce in her this unmoored sense of herself but also to make it a reality. Using examples and analysis, Abramson gives an account of gaslighting and its immorality, and argues that such a discussion can help us understand other aspects of social life—from racism and sexism to the structure of interpersonal trust.