In this age the impact of nano-electronics is ubiquitous. Everyone is familiar with the amazing performance of the intel microprocessor, or the smart phone, which is powered by a billion transistors, each having an active region of only a few nanometers. This implies that only a "few hundred atoms" reliably perform the necessary "building block" operations required for today's computing power. This lecture delves about the less appreciated by-product of the nano-electronic revolution - namely the deeper understanding of current flow through nanostructures. Starting from the very basics, this talk will cover aspects of understanding the working of various emerging and exploratory technologies including nanotransistors, spintronic devices, and nanoscale power generators and refrigerators.