Debian is a distribution of Linux that is considered extremely user friendly for those new to using Linux. It contains many utilities that are commonly used while working with Linux preinstalled, and is compatible with a lot of the peripherals that you would use with a computer, such as Wi-Fi cards and USB devices.

Raspbian is a modified version of Debian specifically designed to run on Raspberry Pi devices. There are drivers for the GPIO pins, USB Wi-Fi devices, and expansion slots on the Pi that allow you to attach a specific display and camera. 

There are two flavors of Raspbian—Raspbian Full and Raspbian Lite. Full has a graphical desktop with programs aimed at educational programming and development. Lite (which we will be using for the projects in this book) only has a command-line interface, but still has full functionality when it comes to Raspberry Pi peripherals. As of the time of writing, the current version of Raspbian is 4.14, nicknamed Stretch.