Landau Fermi liquids and beyond Quasiparticle concept Pomeranchuk stability conditions Collective excitations and zero sound Scattering theory Fermi liquid regime of the Kondo problem Response of an ideal Fermi gas Collective excitations Effect of disorder on electron interactions Bridging phenomenological and microscopic aspects Effect of ampere forces in Fermi liquids Overscreened Kondo model and Nozières Blandin theory Electron lifetime in a mesoscopic conductor Marginal Fermi liquids This book consolidates the older and more recent concepts on weakly interacting fermions where traditional many body techniques are adequate. Targeting primarily the advanced undergraduates and graduates the author has included plenty of examples and problems from contemporary topics of research