Mercury 4.0 is a powerful software tool developed by the Cambridge Crystallographic Data Centre (CCDC) for crystal structure visualization, analysis, design, and prediction. Initially launched in 2001 as a visualization tool, Mercury has evolved significantly over the years to meet the needs of chemical crystallography and crystal engineering communities. It now offers advanced functionalities such as ray-traced graphics, 3D printing, structure editing, molecular shell analysis, and integration with the Cambridge Structural Database (CSD). Mercury also includes the CSD-Community, which provides free software and services for the scientific community, and the CSD-System, which includes tools like WebCSD, ConQuest, Data Analysis, Mogul, and IsoStar. The CSD-Materials component enables exploration and analysis of solid-state materials, including polymorph assessment, co-crystal design, and structure analysis. Mercury 4.0 introduces new features such as the Hydrate Analyser, Solvate Analyser, Conformer Generator, and structure solution from powder data. It also includes the CSD Python API for scripting and automation. Mercury is widely used by researchers in various fields and is supported on multiple platforms. The software continues to evolve based on the needs of the scientific community, with new features and functionalities added to enhance its capabilities in crystallography and materials science.Mercury 4.0 is a powerful software tool developed by the Cambridge Crystallographic Data Centre (CCDC) for crystal structure visualization, analysis, design, and prediction. Initially launched in 2001 as a visualization tool, Mercury has evolved significantly over the years to meet the needs of chemical crystallography and crystal engineering communities. It now offers advanced functionalities such as ray-traced graphics, 3D printing, structure editing, molecular shell analysis, and integration with the Cambridge Structural Database (CSD). Mercury also includes the CSD-Community, which provides free software and services for the scientific community, and the CSD-System, which includes tools like WebCSD, ConQuest, Data Analysis, Mogul, and IsoStar. The CSD-Materials component enables exploration and analysis of solid-state materials, including polymorph assessment, co-crystal design, and structure analysis. Mercury 4.0 introduces new features such as the Hydrate Analyser, Solvate Analyser, Conformer Generator, and structure solution from powder data. It also includes the CSD Python API for scripting and automation. Mercury is widely used by researchers in various fields and is supported on multiple platforms. The software continues to evolve based on the needs of the scientific community, with new features and functionalities added to enhance its capabilities in crystallography and materials science.