Geometry deals with stereochemistry. It must know the present structural model of the molecule and the standard geometry for that molecule. The means of describing this information is presented in the ``TNT Sequence File'' and the ``Standard Geometry Definition''chapters of the TNT Users' Guide. To allow the program to find ``bad'' contacts it must be given the minimal distances allowed between each atom type as well as the symmetry operators for the structure's space group. This information is entered on CONTACT, LATTICE, and OPERATOR statements.