Fundamental equations for ideal fluids.- Acoustic waves.- Real fluids.- The interstellar medium.- Shock waves.- Turbulence.- Electrodynamics and magnetohydrodynamics.- Motion of a plasma in a magnetic field.- Magnetohydrodynamic waves.- Dust from the interstellar medium.- HII regions.- Stellar Winds.- Supernovae remnants.- The interstellar medium and its components.- Molecular Clouds.- Star formation.