When someone smiles the effects are often positive: a glum mood lifts; an apology is accepted; self-confidence gets a boost; a deal is struck; a flirtation begins. But change the circumstances or the cast of a smile, and the terms shift: A rival grins to get under your skin; a bully’s smirk is unsettling. Smiles are universally recognized for what they convey, yet not necessarily for what they do. Much more than cheerful expressions, smiles are social acts with subtle but powerful consequences. In Lip Service (paperback released as Why Smile? The Science Behind Facial Expressions), Dr. Marianne LaFrance explores the compelling science behind these smiles, revealing that this familiar expression is not as simple as it first may seem. This groundbreaking work shows how the smile (or its telling absence) says much more than we realize—or care to admit. To read it is to learn just how much the smile influences our lives and our relationships.