GDIS is a GTK based program for the display and manipulation of isolated molecules and periodic systems. It is in development, but is nonetheless fairly functional. It has the following features: - Support for several file types (CIF, BIOSYM, XYZ, XTL, MARVIN, and GULP) - A simple molecular creation and manipulation tool - A dialogue for creating starting configurations for molecular dynamics simulations - Assorted tools for visualization (geometry information, region highlighting, etc.) - Animation of BIOSYM files