How do publishers typically update a hardbound volume of a secondary source?

Publishers typically update a hardbound volume of a secondary source by issuing a pocket part or supplement. A pocket part is an additional insert that provides updated information, including new laws, regulations, and relevant case law that have emerged since the volume's initial publication. This method allows for timely updates without requiring the entire volume to be reprinted or released as a new edition, which can be more resource-intensive.

This approach is particularly useful in fields like law, where information can rapidly change and the need for current data is critical. Additionally, a pocket part can easily be added to existing volumes, thereby saving costs and making it a convenient option for both publishers and users of the legal text.