This document discusses smartphones, including their definition as cellular phones that perform computer functions with touchscreens and internet access. It outlines the main types of smartphone operating systems like iOS, Android, and Windows, and lists some of the top smartphone models in 2015 such as the iPhone 6 and Samsung Galaxy S6 for their advantages like consolidating communication and information in a single, portable device. The document also briefly examines the release cycle of iPhone models over time.