Fog Computing is a distributed computing environment that extends the Cloud Computing paradigm to fully support the Internet of Things (IoT) vision. It aims to push the intelligence, processing and storage of data closer to the Edge of the network to provide computer-related services more immediately and near to the interconnected smart things that form part of the IoT. For this reason, Fog Computing is sometimes also referred to as Edge Computing. The two terms are often used interchangeably; however, there are subtle differences. Fog Computing market is currently valued at $22.3 million in 2018; it is expected to expand at an explosive rate to grow to around $205 million over the next five years. With such high level of connectivity of smart devices, Fog Computing appears to be the next big thing for the IoT vision. Although the Cloud paradigm is highly attractive for data-intensive processing requirements, there are a number of inherent limitations that the Fog vision aims to resolve: by reducing the Internet/service latency, increasing the context awareness, conserving the network bandwidth, improving the quality of provision, enhancing the operational efficiency, providing the improved user experience and speeding up the real-time processing as well as storing of sensitive data close to where the data are generated. Fog paradigm also provides better support for mobility and the use of mobile communication.