Folded potentials for the description of heavy ion elastic scattering and transfer reactions -- Semi-microscopic approach to the imaginary part of the heavy ion optical potential -- Fusion barriers -- Use of semiclassical quantities in transfer reactions -- Oscillations in the angular distributions of heavy-ion transfer reactions -- Semi-classical description of elastic and inelastic heavy ion scattering -- Wave mechanical aspects of heavy ion collisions -- Surface waves and surface resonances in heavy-ion reactions -- Two-step processes -- Approaches to the interpretation of heavy ion transfer reactions at high energies -- The analysis of high energy heavy-ion transfer reactions -- Friction model for heavy-ion collisions and its application to heavy ion fusion and deep inelastic reactions -- Fusion and fission induced by heavy ions -- Deep inelastic transfer reactions and the formation of a double nuclear system -- Critical discussion of the concept of critical angular momentum in heavy ion reactions -- Summary.