This document discusses duplicate publication, which occurs when a published work is published more than once without proper acknowledgment or justification. This wastes resources and delays scientific progress. It can affect researchers, institutions, journals, and the scientific community. Examples include presenting the same findings in multiple publications or submitting the same manuscript to multiple journals simultaneously. Guidelines state authors should not duplicate content and should acknowledge prior publications. If duplication cannot be avoided, authors must obtain permission and acknowledge the primary source. The document also provides two case studies as examples.