Josephson-effect linear amplifiers now operate at the fundamental quantum limit on noise temperature for linear amplifiers. So why not do this old problem - quantum limits on the performance of linear amplifiers - right, using the modern tools of quantum information theory? I will discuss the general limits on the performance of linear amplifiers, both those that act deterministically and those that, like air travel, only work some of the time. All of this illustrates how an old problem - in this case, a problem 70 years old - just keeps on giving as improving experimental techniques pose new questions and new theoretical tools allow those questions to be answered.