Trademark law has expanded dramatically in the last fifty years, with a number of trends combining to give trademark owners something they have never had before–protection of marks akin to the protection given real property. Professor Lemley evaluates these changes, and suggests that they are not supported by the economic learning on the functions of trademarks and advertising. He argues that many of these legal developments are unwarranted, particularly the cases which give trademark owners power to prevent political and social commentary, or to own the trademark as a thing in itself.