Geometry and physics of the Geant4 toolkit for high and medium energy applications

The current status of the Geant4 toolkit and the recent developments for the geometry, electromagnetic and hadronic physics for medium and high energy are presented. The focus of many recent improvements of the toolkit are key applications including the simulation of large Hadron collider (LHC) experiments at CERN. These developments and physics model extensions provide new capabilities and improvements for other applications of the toolkit for radiation studies in high energy physics (HEP), space and medical research.