[en] Medium energy pion-nucleus reactions have been studied. Detailed predictions for pion inelastic scattering, charge exchange and quasi elastic scattering are presented. (i) Inelastic scattering of pions from ¹⁶O for initial pion laboratory kinetic energies of 69.5 and 180 MeV. All of the calculations have been done in the distorted wave impulse approximation (DWIA) using a separable fixed scatterer pion-nucleon interaction to generate the off-shell pion-nucleon t-matrix operating between the initial pion and final pion distorted waves and nuclear wavefunctions. The harmonic oscillator shell model and the simple Tamm-Dancoff approximation have been used to generate the initial and final nuclear wavefunctions. A comparison of π^- and π⁺ scattering showing the effects of the Coulomb interaction is presented and it is found that one may ignore the effect of the Coulomb interaction for the studies of pion inelastic scattering at these energies. A comparison of the pion-¹⁶O inelastic scattering angular distribution using the distorted wave impulse approximation (DWIA) and plane wave impulse approximation (PWIA) is made to demonstrate the typical effects of distortion and absorption. (ii) (π^-, π⁰) Charge exchange from ⁴⁸Ca for initial pion kinetic energy of 69.5 MeV. The predictions for pion single charge exchange of ⁴⁸Ca indicate that this interaction would be useful for studying the location of the T greater than states arising from the splitting of the giant dipole resonance in T = 0 nuclei. (iii) Quasi elastic scattering of pions from ¹⁶O and ⁴He using simple nuclear models. We have studied the q (momentum transfer); w (energy loss) dependence of the quasi elastic scattering for initial pion laboratory kinetic energies of 69.5 and 180 MeV. Results indicate that it should be possible to resolve the high spin T = 0 states from the quasi elastic background noise