The eleventh issue of the series "What Physicists Think About" is devoted to lasers - one of the most impressive discoveries of modern physics. Articles belonging to major foreign scientists involved in the development and improvement of lasers have been translated from popular science magazines - the American Scientific American and the French La Recherche. They are written vividly and fascinatingly and combine accessibility (starting with the level of readers with secondary education), clarity and rigor of presentation of the essence of scientific problems and achievements. The purpose of the collection is to acquaint wide readership with the principles of work, application and prospects of lasers.