The CAN protocol is now used in applications beyond the original purposes for which it was conceived. Its reliability makes it an ideal protocol in applications where you can not leave any margin of error within your data transmission channel. In this tutorial, after a brief introduction of the CAN applications, the CAN 2.0 specification will be described. At the end of the tutorial, the reader should be able to use any CAN library and have a good background to tackle a microcontroller datasheet and write its own CAN library.