Abstract Some aspects of reactions induced by intermediate energy heavy ions, with a special emphasis on experiments with 85 MeV/ nucleon 12C, are discussed and compared to results at low and relativistic energies. A transition from mean field to independent nucleon behavior is suggested by an increase of nuclear transparency deduced from reaction cross section measurements. Projectile-like fragment distributions, while demonstrating a a typical high energy fragmentation behavior, also exhibit the characteristics of the low energy regime. Light fragments, associated with large parallel momentum transfer may result from total explosion. Proton emission is investigated and discussed in terms of extreme models such as thermal equilibrium and nucleon-nucleon scattering. Finally pion production data are well explained by single nucleon-nucleon inelastic scattering.