Jupyter Notebook is an open-source tool that lets you mix executable code, results, charts, and explanatory text in a single interactive document. It is the standard workbench for data scientists: you run code cell by cell, see outputs immediately, and document your reasoning alongside. A data analyst at a Moroccan telecom operator might use a notebook to explore churn data, visualize trends, and share the annotated analysis with managers. Google Colab offers the same experience free in the browser.