The Python 3 language is described: data types, operators, branching and selection conditions, loops, regular expressions, functions, classes, working with files and directories, interaction with Windows mechanisms, frequently used modules of the standard library. Particular attention is paid to the PyQt library, which allows you to create applications with a graphical interface. Tools for creating and displaying windows, main components (buttons, fields, fields, lists, tables, menus, toolbars, etc.) are described.