This set of survey talks presented to graduate students serves as a thorough exposition of the subject. The study of complex fluids (with internal structure) is important for theoretical purposes but also, and maybe even more so, for applied research. The reader will find papers on colloid mixtures, the structure of DNA mesophases, ferrofluids, chain dynamics, liquid crystals, computer simulations of macromolecules, fluidization, emulsions, relaxations and many other related topics.