In this chapter, we introduce the CUQIpy package and its main features. We provide information on how to run the code notebooks in this book. We also provide a very simple example of solving a Bayesian inverse problem (BIP) using CUQIpy: “Probably the simplest BIP in the world”. This example is presented in two versions: A short version which is right to the point and a long version which explains more details about the code and gives some exercises.