This book provides an in-depth technical overview of six generations of Wi-Fi standards covering protocol, implementation, and system deployment aspects. The new features and capabilities of the latest sixth generation standard called Wi-Fi6, and its security are described. Alternate use cases of Wi-Fi are addressed, including 60 GHz Wi-Fi (802.11ad/ay) and indoor positioning using Wi-Fi. Wi-Fi6 is described as it compares 5G technology. Readers will understand practical implementation challenges, problems, and common solutions relevant to Wi-Fi deployment in different environments.