This is a case study of trademark infringement disputes. One of the authors (M. Cosgrove) incorporated The Econoclast, Inc. in 1979. The company provides capital market publications to financial and nonfinancial institutions, and owns the trademark Econoclast. Over the years, others have attempted to use the same name for similar services. This case study presents the practical steps that Cosgrove undertook to prevent infringement of his trademark in various cases that occurred since our prior paper was published in 2005 (Cosgrove, Marsh and Chester.) The paper also explains the basics of trademark law, the meaning of trademark infringement, and obligations of the trademark owner.