Qt is a cross-platform application framework that was created for use with C++. Available in both commercial and open source licenses (General Public License (GPL) v3 and Lesser General Public License (LGPL) v3, specifically), it is widely used by open source projects such as KDE Plasma and Oracle VirtualBox, commercial software such as Adobe Photoshop Elements and Autodesk Maya, and even embedded software in products from companies such as LG and Panasonic. Qt is currently owned and maintained by the Qt company (https://www.qt.io).
In this book, we're going to be working with the open source release of Qt 5.12. If you're using Windows, macOS, or a major Linux distribution, you should not need to install Qt explicitly; it will be installed automatically when you install PyQt5.
Qt is officially pronounced cute, though many people say, Q T.
