The paper discusses the evolution of the *Mercury* program, originally developed by the Cambridge Crystallographic Data Centre (CCDC) as a crystal structure visualization tool. Over the years, *Mercury* has evolved to become a comprehensive platform for analysis, design, and prediction in chemical crystallography and crystal engineering. The program now includes advanced features such as ray-traced graphics, 3D printing capabilities, structural editing tools, and molecular shell analysis. It also integrates with the Cambridge Structural Database (CSD) and its associated software suite, providing access to a wealth of crystal structure data and tools for data analysis, knowledge-based analysis, and solid-state material design. The paper highlights the recent release of *Mercury* version 4.0, which introduces new functionalities for polymorph assessment, co-crystal design, full interaction maps, hydrate and solvate analysis, conformer generation, and structure solution from powder data. The program's flexibility is further enhanced by its Python API, allowing users to run custom scripts and perform tailored analyses. The authors emphasize the ongoing collaboration between the CCDC and the scientific community to ensure that *Mercury* remains a cutting-edge tool for crystallographic research.The paper discusses the evolution of the *Mercury* program, originally developed by the Cambridge Crystallographic Data Centre (CCDC) as a crystal structure visualization tool. Over the years, *Mercury* has evolved to become a comprehensive platform for analysis, design, and prediction in chemical crystallography and crystal engineering. The program now includes advanced features such as ray-traced graphics, 3D printing capabilities, structural editing tools, and molecular shell analysis. It also integrates with the Cambridge Structural Database (CSD) and its associated software suite, providing access to a wealth of crystal structure data and tools for data analysis, knowledge-based analysis, and solid-state material design. The paper highlights the recent release of *Mercury* version 4.0, which introduces new functionalities for polymorph assessment, co-crystal design, full interaction maps, hydrate and solvate analysis, conformer generation, and structure solution from powder data. The program's flexibility is further enhanced by its Python API, allowing users to run custom scripts and perform tailored analyses. The authors emphasize the ongoing collaboration between the CCDC and the scientific community to ensure that *Mercury* remains a cutting-edge tool for crystallographic research.