Corrosion is a universal natural phenomenon that causes degradation in metal and alloy properties by chemical or electrochemical interaction with their environment. In the United States, the total direct cost of corrosion is estimated at about 300 billion dollars per year, which is about 3.2 percent of the domestic product. This means corrosion has a huge economic loss on national infrastructure, such as bridges, chemical processing, buildings, and waste water treatment. In addition, corrosion not only increases the costs of components, but it is also responsible for life losses or injuries to people, and it reduces the value of goods owing to deterioration of appearance as well as safety hazards. Thus, by retarding either the cathodic or anodic reactions, the rate of corrosion can be reduced by coating, addition of chemical additives (corrosion inhibitors) etc. Hence, the aim of this research paper is to provide an overview of corrosion, its history, importance, classification, and preventive measures.