Principles of MIC: Is introduction to corrosion, thermodynamic and kinetic of corrosion, corrosion rate, passivity and polarization. Corrosion types also mention in this book especially Microbiological Influenced Corrosion which discusses the mechanism of corrosion by living microorganisms especially in pipelines and how detect them, in addition to review some examples of this type of corrosion may be occur in metals and alloys.