Introduction.- A Radiation Damage Cascade.- Electronic Excitations in Radiation Damage - a Review.- Theoretical Background.- Simulating Radiation Damage in Metals. A Framework for Simulating Radiation Damage in Metals.- The Single Oscillating Ion.- Semi-calssical Simulations of Collision Cascades.- The Nature of the Electronic Excitations.- The Electronic Forces.- Channelling Ions.- The Electronic Drag Force.-Concluding Remarks.- A. Selected Proofs.-...