Hotel Sued Over Use of Dewey Decimal System Who knew that the Dewey Decimal System was trademarked? And how do you trademark a system, anyway? The New York Times is reporting that the "owners" of the Dewey Decimal System trademark have sued the owners of the Library Hotel in New York for using the system without a license. This is one complaint I would love to read, since I have a feeling that the write up probably isn't capturing the whole issue.